Browsing by Author "Chung, Yao-Hsing"

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A Balanced Resource Scheduling Scheme With Adaptive Priority Thresholds for OFDMA Downlink Systems
(2012-03-01)
Chung, Yao-Hsing
;
Chang, Chung-Ju
;
交大名義發表
;
電機工程學系
;
National Chiao Tung University
This paper proposes a new balanced resource scheduling (BRS) scheme with adaptive priority thresholds for orthogonal frequency-division multiple-access (OFDMA) downlink systems. The BRS scheme achieves an excellent balance between quality-of-service (QoS) requirement guarantee and system throughput enhancement, whereas conventional schemes cannot explicitly and accurately control this tradeoff. Based on the adaptive priority threshold of each user, the BRS scheme first performs a priority-based resource allocation (RA) algorithm for users whose priority value is larger than its priority threshold to fulfill the QoS requirement. The BRS scheme then performs a channel-state-information (CSI)-based RA algorithm for the remaining users to enhance system throughput. To achieve balance between QoS guarantee and throughput enhancement, a fuzzy inference priority threshold generator adaptively and intelligently adjusts the priority threshold of each user. Simulation results show that the proposed BRS scheme with adaptive priority threshold enhances the system throughput by 16%, 8.5%, 8.2%, and 46.8% at traffic load of 0.93, compared with conventional adaptive radio RA (RRA), utility-based RRA, utility-based throughput maximization and complexity reduction scheduling, and fairness and QoS guarantee scheduling with fuzzy controls schemes, respectively, under a QoS requirement guarantee. This approach also outperforms the BRS scheme with fixed priority thresholds in both throughput enhancement and QoS guarantee.
A Coordination Based Resource Management Scheme with QoS Provisioning for Multicell OFDMA Downlink Systems
(2014-01-01)
Chung, Yao-Hsing
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Chang, Chung-Ju
;
電機資訊學士班
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Undergraduate Honors Program of Electrical Engineering and Computer Science
In this paper, we propose a coordination based resource management (CBRM) scheme with quality-of-service (QoS) provisioning for multicell OFDMA downlink systems. The proposed CBRM scheme cooperates with the multiple point deployment and the enhanced fractional frequency reuse (FFR). To solve the intra-cell interference brought by multiple point deployment, the CBRM scheme adopts a utility function to coordinate TPs and then maximizes system throughput and fulfills QoS requirements. Simulation results show that the CBRM scheme enhances the system throughput by amounts of 113% and 89% compared to the conventional FFR scheme [1] and the dynamic interference avoidance (DIA) scheme [6], respectively. Moreover, the CBRM scheme provides good QoS guarantee for both real-time and non-real-time
A Cross-Layer Congestion Avoidance Routing Scheme in Vehicular Ad Hoc Networks
(2014-01-01)
Yang, Chiao-Ling
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Chung, Yao-Hsing
;
Chen, Chen-Yu
;
Chang, Chung-Ju
;
電機資訊學士班
We propose a cross-layer congestion avoid-ance routing (CCAR) scheme for VANETs based on IEEE 802.11p/WAVE (wireless access in vehicular environment) protocol. Due to highly dynamic network topology, the forwarders are selected one by one. The CCAR scheme first adjust the number of candidates adaptively so that senders have high probability to find a candidate as the forwarder. Then it dynamically adjusts the selection probability of each service channel (SCH) based on traffic load of SCHs to make channel load balanced. Finally, the CCAR scheme takes the number of co-channel senders, the loads of each possible forwarder, and the vehicular moving direction into account to determine the most appropriate route for senders. Simulation results show that the proposed CCAR scheme achieves lower packet delay (higher system uplink through-put) than the conventional GyTAR and AODV schemes by amounts of 95% and 95.7%, (8.4% and 19.2%,) respectively, when the number of vehicles is 150.
A User-Differentiation-based Resource Allocation Scheme for OFDMA Downlink Systems
(2012)
Chung, Yao-Hsing
;
Chang, Chung-Ju
;
Zhang, Zhaoyang
;
交大名義發表
;
National Chiao Tung University
This paper proposes a new user-differentiation-based resource allocation (UDRA) scheme for OFDMA downlink systems. The UDRA scheme can strike a good balance between quality-of-service (QoS) requirement guarantee and system throughput enhancement, whereas conventional schemes cannot explicitly and accurately control this tradeoff. The UDRA scheme first performs a utility-based resource allocation algorithm for urgent users to fulfill QoS requirement, then it performs a maximum-sum-rate resource allocation algorithm for regular users to enhance system throughput. To achieve the balance between QoS guarantee and throughput enhancement, the UDRA scheme further designs a fuzzy logic user identifier (FLUI) to intelligently differentiate users from urgent and regular. Simulation results show that the proposed UDRA scheme enhances the system throughput by 23.1%, 14.1%, and 9.7%, compared to the PSRA [1], ARRA [2], and U-TMCR [3] schemes, respectively, under a QoS requirement guarantee.
Balanced Resource Scheduling Scheme With Adaptive Priority Thresholds for OFDMA Downlink Systems
(2012-03-01)
Chung, Yao-Hsing
;
Chang, Chung-Ju
;
電機工程學系
;
Department of Electrical and Computer Engineering
This paper proposes a new balanced resource scheduling (BRS) scheme with adaptive priority thresholds for orthogonal frequency-division multiple-access (OFDMA) downlink systems. The BRS scheme achieves an excellent balance between quality-of-service (QoS) requirement guarantee and system throughput enhancement, whereas conventional schemes cannot explicitly and accurately control this tradeoff. Based on the adaptive priority threshold of each user, the BRS scheme first performs a priority-based resource allocation (RA) algorithm for users whose priority value is larger than its priority threshold to fulfill the QoS requirement. The BRS scheme then performs a channel-state-information (CSI)-based RA algorithm for the remaining users to enhance system throughput. To achieve balance between QoS guarantee and throughput enhancement, a fuzzy inference priority threshold generator adaptively and intelligently adjusts the priority threshold of each user. Simulation results show that the proposed BRS scheme with adaptive priority threshold enhances the system throughput by 16%, 8.5%, 8.2%, and 46.8% at traffic load of 0.93, compared with conventional adaptive radio RA (RRA), utility-based RRA, utility-based throughput maximization and complexity reduction scheduling, and fairness and QoS guarantee scheduling with fuzzy controls schemes, respectively, under a QoS requirement guarantee. This approach also outperforms the BRS scheme with fixed priority thresholds in both throughput enhancement and QoS guarantee.
Opportunistic Scheduling with Economized CSI Feedback for OFDMA/TDD Downlink Systems
(2009)
Chung, Yao-Hsing
;
Chang, Chung-Ju
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電信工程研究所
;
Institute of Communications Engineering
In this paper we propose an economized-CSI (channel state information) opportunistic scheduling (ECOS) scheme for OFDMA/TDD downlink systems. The ECOS scheme consists of a quality-of-service (QoS) guarantee scheduling (QGS) algorithm and a CSI overhead reduction (COR) algorithm. The QGS algorithm guarantees QoS requirements by adjusting priority value and anticipated rate of users dynamically. In addition, it achieves balance between QoS guarantee and throughput maximization by employing a priority threshold. The COR algorithm performs admissible user selection to economize the amount of CSI overhead. Since all users do not need to feed back CSI every frame, the transmission power used for CSI reporting is economized. Besides, the COR algorithm can reduce the computation complexity of the QGS algorithm because the number of users to be scheduled is reduced. Simulation results show that the proposed ECOS scheme greatly reduces the uplink bandwidth occupancy of CSI feedback. Also, it achieves high system throughput and maintains QoS guarantee at high traffic load.