Browsing by Author "Sivalingam, Krishna M."

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Analytical Model For Power Savings in LTE Networks using DRX Mechanism
(2015)
Varma, Syama R.
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Sivalingam, Krishna M.
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Tung, Li-Ping
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Lin, Ying-Dar
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資訊工程學系
This paper presents an analytical model, based on a semi-Markov process, for determining the power savings achieved in a User Equipment (UE) device of a Long Term Evolution (LTE) network using the Discontinuous Reception (DRX) mechanism. Systems with and without packet buffers and the UE and enodeB are presented in this paper. Using the models, it is possible to determine the savings in power attainable by the UE when different DRX sleep cycles and timers are used. The analytical models has been validated using a discrete-event simulation model. The numerical results show that it is possible to obtain UE power savings of up to 63%.
Dynamic DRX Algorithms for Reduced Energy Consumption and Delay in LTE Networks
(2014)
Varma, Syama R.
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Sivalingam, Krishna M.
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Tung, Li-Ping
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Lin, Ying-Dar
;
資訊工程學系
The Long Term Evolution (LTE) standard specifies the Discontinuous Reception Mechanism (DRX) mechanism for saving power at the User Equipment (UE). Here, a UE switches off its RF circuitry when there are no packets to be transmitted or received. The existing DRX algorithms use static operational parameters that are determined by the evolved nodeB (eNB) at the start of a UE\'s session. During the switch-off period, packets destined to the UE are buffered in the eNB leading to higher packet latency. This paper presents two adaptive algorithms to dynamically adjust the DRX parameters, in order to reduce both energy consumption and the extra delay incurred. The algorithms use application Quality-of-Service (QoS) and Channel Quality Information (CQI) to adjust the DRX parameters. Performance studies based on ns3 simulator show that the algorithms are able to reduce packet delay compared to static DRX by up to 60%, 60% and 75% and reduce energy consumption by up to 75%, 43% and 90% for video streaming, VoIP and bursty data applications respectively.
Reducing power consumption in LTE data scheduling with the constraints of channel condition and QoS
(2014-12-24)
Tung, Li-Ping
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Lin, Ying-Dar
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Kuo, Yu-Hsien
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Lai, Yuan-Cheng
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Sivalingam, Krishna M.
3GPP has developed the Discontinuous Reception (DRX) power saving mechanism, which periodically turns off the radio interface to reduce the power consumption. However, packets cannot be received during the turn-off duration, as a result that the Quality of Services (QoS) may be violated. Therefore, optimal DRX parameters should be configured to satisfy QoS and minimize power consumption. In addition, channel condition may be unstable during the transmission, so the DRX parameters should also be dynamically adjusted. In this paper, we propose the Dynamic Scheduling with Extensible Allocation and Dispersed Offsets (DXD) scheme, which is composed of two algorithms, DRX parameters decision, to determine DRX period by considering channel condition and QoS constraints, and DRX-aware scheduling, to determine whether to extend the on duration so that QoS would not be affected by DRX. Simulation results demonstrate that the proposed DXD approach can reduce power consumption up to 96.7% compared to No-DRX scheme and guarantee QoS as good as No-DRX scheme. In addition, the power consumption can be reduced by 70.1% and 45.7% compared to the Fixed-DRX (100 ms), start-offset scheme and IS scheme in good channel condition. Our approach effectively reduces power consumption in varied channel conditions and high loading system and still achieves better delay satisfaction ratio than others. (C) 2014 Elsevier B.V. All rights reserved.
Reducing Power Consumption in LTE Data Scheduling with the Constraints of Channel Condition and QoS
(2014-01-01)
Tung, Li-Ping
;
Lin, Ying-Dar
;
Ku, Yu-Hsien
;
Lai, Yuan-Cheng
;
Sivalingam, Krishna M.
3GPP has developed the Discontinuous Reception (DRX) power saving mechanism, which periodically turns off the radio interface to reduce power consumption. However, packets cannot be received during the on period, as a result that the Quality of Services (QoS) may be violated. In addition, channel condition may be unstable during the transmission, so the optimal DRX parameters should also be dynamically adjusted. In this paper, we propose the Dynamic Scheduling with Extensible Allocation and Dispersed Offsets (DXD) scheme, which is composed of two algorithms, DRX parameter decision algorithm, to determine the DRX period by considering channel condition and QoS constraints, and DRX-aware scheduling algorithm, to determine whether to extend the on duration so that QoS would not be affected by DRX. Simulation results demonstrate that our DXD approach can reduce power consumption up to 96.9% compared to no DRX scheme and guarantee QoS as good as no DRX scheme.