Browsing by Author "Shen, S"

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A cellular neural network and utility-based scheduler for multimedia CDMA cellular networks
(2005)
Shen, S
;
Chang, CJ
;
電信工程研究所
;
Institute of Communications Engineering
In this paper a cellular neural network and utility (CNNU)-based scheduler is proposed for multimedia CDMA cellular networks supporting differentiated quality-of-service (QoS). The cellular neural network is powerful for complicated optimization problems and implementable by circuits with rapid convergence to a desired equilibrium; the utility-based scheduling algorithm can efficiently utilize the radio resource for system and provide QoS requirements and fairness for connections. A relevant utility function for each connection is here defined as its radio resource function further weighted by both a QoS requirement deviation function and a fairness compensation function. The CNNU-based scheduler determines a radio resource assignment vector for all connections so that the overall system utility is maximized and the system throughput can be achieved as high as possible. At the same time, the performance measures of all connections are kept closed to their QoS requirements in an efficient way.
A utility-based scheduling algorithm with differentiated QoS provisioning for multimedia CDMA cellular networks
(2004)
Shen, S
;
Chang, CJ
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, we propose a utility-based scheduling algorithms with three generalized design aspects of link adaptation, QoS requirement achievement, and weighted fairness for multimedia CDMA network. Both dedicated and shared channels serve different classes of services. Per class QoS requirements are defined by both packet level, such as BER, and call level, such as, delay bound, packet dropping ratio, and minimum transmission rate. The utility function of each connection is the radio resource function weighted by both the QoS requirement achievement function and weighted fairness function. The system resource is scheduled via maximizing the overall system utility while the weighted fairness and the QoS requirements are kept. The optimal scheduling solution is derived as a resource assignment vector for active connections by solving the optimization of overall utility function via a polymatroid structure.
Intelligent call admission control for differentiated QoS provisioning in wideband CDMA cellular systems
(2000)
Chang, CJ
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Shen, S
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Lin, JH
;
Ren, FC
;
電信工程研究所
In this paper, we propose intelligent call admission control for wideband CDMA cellular systems to support differentiated QoS requirements. The intelligent call admission controller (ICAC) adopts fuzzy and neural network techniques to make admission decision for a new call request by considering the QoS measures of all service types, predicted next-step existing-call interference, and estimated new-call interference. It contains a fuzzy call admission processor, a pipeline recurrent neural network (PRNN) interference predictor, and a fuzzy equivalent interference estimator. Simulation results indicate that ICAC attains better performance in keeping QoS guaranteed, blocking probability and admitted number of users. Furthermore, ICAC is more adaptive and stable than SIR-based CAC in wideband CDMA cellular systems.
Intelligent call admission control for wideband CDMA cellular systems
(2004-09-01)
Shen, S
;
Chang, CJ
;
Huang, CY
;
Bi, Q
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電子工程學系及電子研究所
In this paper, we propose intelligent call admission control for wideband code-division multiple-access (CDMA) cellular systems to support differentiated quality-of-service (QoS) requirements, guarantee the forced termination probability of handoffs, and maximize the spectrum utilization. The intelligent call admission controller (ICAC) contains a fuzzy call admission processor to make admission decision for a call request by considering QoS measures such as the forced termination (drop call) probability of handoff, the outage probability of all service types, the predicted next-step existing-call interference, the link gain, and the estimated equivalent interference of the call request. The pipeline recurrent neural network (PRNN) is used to accurately predict the next-step existing-call interference, and the fuzzy logic theory is applied to estimate the new/handoff call interference based on knowledge of effective bandwidth method. Simulation results indicate that ICAC achieves system capacity higher than conventional CAC schemes by an amount of more than 10% in both low and high moving speed cases. Moreover, ICAC can cope with the unpredictable statistical fluctuation of wireless multimedia traffic; it always fulfill QoS requirements for all service types and keep the forced termination probability satisfied, while the CAC of multimedia calls (MCAC) and SIR-based CAC with intercell interference prediction (PSIR-CAC) fail to adapt to the variation of traffic conditions.
Outage-based fuzzy call admission controller with multiuser detection for WCDMA systems
(2005-10-01)
Chen, YH
;
Chang, CJ
;
Shen, S
;
電信工程研究所
;
Institute of Communications Engineering
An outage-based fuzzy call admission controller with multiuser detection (OFCAC-MUD) is proposed for wideband code division multiple access (WCDMA) systems. The OFCAC-MUD determines the new call admission based on the uplink signal-to-interference ratios from home and adjacent cells and system outage probabilities. The OFCAC-MUD possesses both the effective reasoning capability of a fuzzy logic system and the aggressive processing ability of MUD. Simulation results reveal that OFCAC-MUD without power control (PC) improves the system capacity by 70.5% as compared to an SIR-based CAC-RAKE with perfect PC. It also enhances the system capacity by 53.9% as compared to an OFCAC-RAKE with perfect PC, by 6.7% as compared to an SIR-based CAC-MUD without PC and by 12.9% as compared to an OFCAC-MUD with perfect PC, given the same outage probability requirements. Moreover, OFCAC-MUD can prevent the violation of outage probability requirements in the hotspot environment, which is hardly achieved by SIR-based CAC.
Radio resource index for WCDMA cellular systems
(2004-07-01)
Shen, S
;
Chang, CJ
;
電信工程研究所
;
Institute of Communications Engineering
In this letter, a radio resource index (RRI) is derived to estimate the radio resources of a connection in WCDMA cellular systems. An analytical model is presented and large deviation techniques are used. The RRI can transform traffic parameters and multiple quality-of-service (QoS) requirements into a measure of radio resources using a unified metric.
The radio resource index for real-time service in WCDMA cellular systems
(2002)
Shen, S
;
Chang, CJ
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, a radio resource index (RRI) is derived to estimate the radio resource required for a call connection in WCDMA cellular systems. An analytical model is proposed and large deviation techniques are adopted to obtain the RRI. The RRI can transform traffic parameters and quality-of-service (QoS) requirements of the call connection into a measure of resource in a unified metric, while keeping QoS requirements of existing calls guaranteed.