Browsing by Author "Cheng, RG"

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A power-spectrum based neural fuzzy connection admission mechanism for ATM networks
(1997)
Chang, CJ
;
Lin, SY
;
Shiue, YR
;
Cheng, RG
;
交大名義發表
ATM (asynchronous transfer mode) networks support services with bursty traffic. A sophisticated and real-time admission controller is needed not only to guarantee the required quality-of-service (QoS) for existing calls but also to achieve higher system efficiency. In this paper, we propose a power-spectrum based neural fuzzy connection admission control (PNFCAC) mechanism for an ATM network. Power-spectrum of input process explicitly describes the correlation behavior of input traffic and has a great impact on the queueing behavior of an ATM net work. The neural fuzzy controller has been successfully applied to deal with the complex problem which can not be analyzed by classical methods based on probability theory and bivalent logic for recent years. Under the constraint of QoS, we construct a decision hyperplane of the connection admission control according to parameters of the power spectrum. We further adopt the learning/adapting capabilities of the neural network to adjust the optimum location of the boundary between these two decision space. Simulation results show that the PNFCAC mechanism provides a superior system utilization over the conventional CAC schemes and the neural fuzzy CAC using time-domain analysis, while keeping the QoS contract.
A QoS-provisioning neural fuzzy connection admission controller for multimedia high-speed networks
(1999-02-01)
Cheng, RG
;
Chang, CJ
;
Lin, LF
;
電信工程研究所
;
電信研究中心
This paper proposes a neural fuzzy approach for connection admission control (CAC) with QoS guarantee in multimedia high-speed networks. Fuzzy logic systems have been successfully applied to deal with traffic-control-related problems and have provided a robust mathematical framework for dealing with real-world imprecision. However, there is no clear and general technique to map domain knowledge on traffic control onto the parameters of a fuzzy logic system. Neural networks have learning and adaptive capabilities that can be used to construct intelligent computational algorithms for traffic control. However, the knowledge embodied in conventional methods is difficult to incorporate into the design of neural networks. The proposed neural fuzzy connection admission control (NFCAC) scheme is an integrated method that combines the linguistic control capabilities of a fuzzy logic controller and the learning abilities of a neural network. It is an intelligent implementation so that it can provide a robust framework to mimic experts' knowledge embodied in existing traffic control techniques and can construct efficient computational algorithms for traffic control. We properly choose input variables and design the rule structure for the NFCAC controller so that it can have robust operation even under dynamic environments. Simulation results show that compared with a conventional effective-bandwidth-based CAC, a fuzzy-logic-based CAC, and a neural-net-based CAC, the proposed NFCAC can achieve superior system utilization, high learning speed, and simple design procedure, while keeping the QoS contract.
Achieving weighted fairness for wireless multimedia services
(2003)
Shih, CY
;
Cheng, RG
;
Chang, CJ
;
電信工程研究所
;
Institute of Communications Engineering
It is important to provide differentiated quality of services (QoSs) for multimedia services over Wireless LAN (WLAN). Fairness is one of the key issues for QoS supporting. In this paper, we proposed a method to achieve weighted fairness for two classes of service operating under the enhanced distributed coordinator function (EDCF) mode of 802.11e. A queueing model is adopted to analyze the behavior of the two classes. The analytical results were verified by computer simulation. Numerical results showed that the weighted goals are easily achieved by adjusting both the arbitration inter frame space (AIFS) and the contention window (CW).
An enhanced traffic marker for DiffServ networks
(2005)
Lin, LF
;
Yan, NY
;
Chang, CJ
;
Cheng, RG
;
電信工程研究所
In this paper, we propose an enhanced traffic marker (ETM) to amend the inappropriate marking in DiffServ networks. The ETM is based on the Two-Rate-Three-Color-Marker (TRTCM) scheme and introduces the feature of aggressive promotion and fair share marking. Simulation results show that the ETM fairly allocates bandwidth among micro-flows and achieves a higher throughput than TRTCM does.
Design of a fuzzy traffic controller for ATM networks
(1996-06-01)
Cheng, RG
;
Chang, CJ
;
電信工程研究所
;
電信研究中心
;
Institute of Communications Engineering
This paper presents the design of a fuzzy traffic controller that simultaneously manages congestion control and call admission control for asynchronous transfer mode (ATM) networks. The fuzzy traffic controller is a fuzzy implementation of the two-threshold congestion control method and the equivalent capacity admission control method extensively studied in the literature. It is an improved, intelligent implementation that not only utilizes the mathematical formulation of classical control but also mimics the expert knowledge of traffic control, We appropriately choose input linguistic variables of the fuzzy traffic controller so that the controller is a closed-loop system with stable and robust operation. We extract knowledge of conventional control methods from numerous analytical data using a clustering technique and then use this knowledge to set parameters of the membership functions and fuzzy control rules via fuzzy set manipulation (linguistically stated but mathematically treated) with the aid of an optimization technique named genetic algorithm (GA). Simulation results show that the proposed fuzzy admission control improves system utilization by a significant 11%, while maintaining the quality of service (QoS) contract comparable with that of the conventional equivalent capacity method. The performance of the proposed fuzzy congestion control method is also 4% better than that of the conventional two-threshold congestion control method.
Design of a power-spectrum-based ATM connection admission controller for multimedia communications
(1998-02-01)
Chang, CJ
;
Lin, CH
;
Guan, DS
;
Cheng, RG
;
電信工程研究所
This paper proposes a power-spectrum-based connection admission controller design in asynchronous transfer mode (ATM) switches for multimedia communications, The controller contains a power-spectrum-indexed table for managing multimedia call requests, where traffic characteristics of call requests are described by the power spectrum, The power spectrum can be obtained from the claimed traffic parameters of peak rate, mean rate, and peak rate duration; the pow er spectrum has been shown to have a dominant effect on system performance, The results show that the proposed power-spectrum-based connection admission control method achieves higher system utilization and lower call-blocking probability than the equivalent-capacity allocation method.
Design of a power-spectrum-based ATM connection admission controller for multimedia communications
(1998-02-01)
Chang, CJ
;
Lin, CH
;
Guan, DS
;
Cheng, RG
;
電信工程研究所
This paper proposes a power-spectrum-based connection admission controller design in asynchronous transfer mode (ATM) switches for multimedia communications, The controller contains a power-spectrum-indexed table for managing multimedia call requests, where traffic characteristics of call requests are described by the power spectrum, The power spectrum can be obtained from the claimed traffic parameters of peak rate, mean rate, and peak rate duration; the pow er spectrum has been shown to have a dominant effect on system performance, The results show that the proposed power-spectrum-based connection admission control method achieves higher system utilization and lower call-blocking probability than the equivalent-capacity allocation method.
Dynamic scheduling framework on an RLC/MAC layer for, general packet radio service
(2003-09-01)
Yang, JS
;
Tseng, CC
;
Cheng, RG
;
資訊工程學系
;
Department of Computer Science
In this paper, we present a traffic-scheduling framework that can dynamically allocate radio resources to a general packet radio service (GPRS) mobile station (MS) based on the interference levels of the radio links and the quality of service (QoS) specification of the MS. The underlying,idea of this scheduling scheme is to preserve more bandwidth for use by those MSs that are within a low interference region so that the limited radio resources can be used more effectively. In this scheme, an MS uses a low transmission rate for data transfer when the MS is within a high interference region to avoid wasting bandwidth by transmitting data in a condition with high interference. In order to compensate for the service loss of the MS, we will allocate more bandwidth to the MS when it is within a low interference region. In addition, we also propose an analytical model that can be used to derive the transmission rate for an MS in a low interference region based on the delay-bound requirement of the MS. The performance results show that our dynamic scheme can utilize the bandwidth more effectively to satisfy various QoS requirements of the MSs in the GPRS system without changing the convolution-coding rate.
Dynamic scheduling framework on RLC/MAC layer for general packet radio service
(2001)
Yang, JS
;
Tseng, CC
;
Cheng, RG
;
資訊工程學系
;
Department of Computer Science
In this paper, we present a traffic-scheduling framework which can dynamically allocate radio resource to GPRS handsets based on the interference levels of the radio links. Essentially, when a mobile station (MS) is within a high interference region, the proposed scheme uses a low transmission rate to reduce bandwidth wastage due to re-transmissions. On the other hand, when the MS is within a low interference region, a high transmission rare is used, in order to fulfill its quality of service (QoS) requirements. One of our contributions is to derive a rate decision analytical model to determine the high and low transmission rates based on the interference conditions and the delay-bound requirement. The performance results show that our dynamic scheme can effectively utilize the bandwidth to satisfy various QoS requirements in the GPRS system without changing the convolution-coding rate.
Neural-network connection-admission control for ATM networks
(1997-04-01)
Cheng, RG
;
Chang, CJ
;
電信工程研究所
;
Institute of Communications Engineering
ATM connection-admission control (CAC) using neural networks offers improvement over conventional CAC but creates some difficulties in real operation, such as complicated training processes. This is because ATM traffic characteristics are quite diverse, and quality of service (QoS) and bandwidth requirements vary considerably. A neural-network connection-admission control (NNCAC) method which can overcome these difficulties by preprocessing neural-network input parameters is proposed. The NNCAC method introduces a unified metric for input-traffic parameters by utilising robust analytical results of the equivalent-capacity method. It diminishes the estimation error of the equivalent-capacity method, due to modelling, approximation unpredictable statistical system, by employing the learning capability of a neural network. The method further considers the congestion status parameter and the cell loss probability, which provides insight information about the system. Simulation results revealed that the proposed NNCAC method provided a 20% system-utilisation improvement over Hiramatsu's neural-network CAC scheme and a 10% system-utilisation improvement over based CAC scheme, while maintaining QoS contracts. It was also found that the NNCAC: method provided utilisation comparable with that of the NFCAC scheme but possessed a lower cell loss probability. NNCAC is suitable for designers who are not familiar with fuzzy-logic control schemes or have no ideas about the requisite knowledge of CAC.
Neural-network connection-admission control for ATM networks
(1997-04-01)
Cheng, RG
;
Chang, CJ
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
ATM connection-admission control (CAC) using neural networks offers improvement over conventional CAC but creates some difficulties in real operation, such as complicated training processes. This is because ATM traffic characteristics are quite diverse, and quality of service (QoS) and bandwidth requirements vary considerably. A neural-network connection-admission control (NNCAC) method which can overcome these difficulties by preprocessing neural-network input parameters is proposed. The NNCAC method introduces a unified metric for input-traffic parameters by utilising robust analytical results of the equivalent-capacity method. It diminishes the estimation error of the equivalent-capacity method, due to modelling, approximation unpredictable statistical system, by employing the learning capability of a neural network. The method further considers the congestion status parameter and the cell loss probability, which provides insight information about the system. Simulation results revealed that the proposed NNCAC method provided a 20% system-utilisation improvement over Hiramatsu's neural-network CAC scheme and a 10% system-utilisation improvement over based CAC scheme, while maintaining QoS contracts. It was also found that the NNCAC: method provided utilisation comparable with that of the NFCAC scheme but possessed a lower cell loss probability. NNCAC is suitable for designers who are not familiar with fuzzy-logic control schemes or have no ideas about the requisite knowledge of CAC.
Power-spectrum-based neural-net connection admission control for multimedia networks
(2002-04-01)
Chang, CJ
;
Lin, LF
;
Lin, SY
;
Cheng, RG
;
電信工程研究所
Multimedia networks need sophisticated and real-time connection admission control (CAC) not only to guarantee the required quality of service (QoS) for existing calls but also to enhance utilisation of systems. The power spectral density (PSD) of the input process contains correlation and burstiness characteristics of input traffic and possesses the additive property. Neural networks have been widely employed to deal with the traffic control problems in high-speed networks because of their self-learning capability. The authors propose a power-spectrum-based neural-net connection admission control (PNCAC) for multimedia networks. A decision hyperplane is constructed for the CAC using power spectrum parameters of traffic sources of connections, tinder the constraint of the QoS requirement. Simulation results show that the PNCAC method provides system utilisation and robustness superior to the conventional equivalent capacity CAC scheme and Hiramatsu's neural network CAC scheme, while meeting the QoS requirement.
PSD-based neural-net connection admission control
(1997)
Chang, CJ
;
Lin, SY
;
Cheng, RG
;
Shiue, YR
;
交大名義發表
ATM (asynchronous transfer mode) systems can support services with bursty traffic. An ATM system needs a sophisticated and real-time connection admission controller not only to guarantee the required quality-of-service (QoS) for existing calls but also to raise the system efficiency. Input process has a power-spectral-density (PSD) which explicitly contains the correlation behavior of input traffic and has a great impact on the system performance. Also, a neural network has been widely applied to deal with traffic control related problems in ATM systems because of its self-learning capability. In this paper, we propose a PSD-based neural-net connection admission control (PNCAC) method for an ATM system. Under the QoS constraint, we construct a decision hyperplane of the connection admission control according to parameters of the power spectrum. We further adopt the learning/adapting capabilities of the neural network to adjust the optimum location of the boundary between these two decision spaces. Simulation results show that the PNCAC method provides a superior system utilization over the conventional CAC schemes by an amount of 18%, while keeping the QoS contract.
QoS-guaranteed fuzzy transmission controller for dynamic TDMA protocol in multimedia communication systems
(2002-10-01)
Ren, FC
;
Chang, CJ
;
Cheng, RG
;
電信工程研究所
;
Institute of Communications Engineering
The paper proposes a QoS-guaranteed fuzzy transmission controller (FTC) for the dynamic TDMA protocol in multimedia communication systems. The dynamic TDMA protocol adopts a mini-slot technique for reducing contention cost, and the mini-slots are further partitioned into multiple MAC regions that users can access with their respective quality-of-service (QoS) requirements. The FTC mainly contains a Sugeno self-tuning fuzzy MAC threshold controller and a fuzzy access controller. The former applies a position-gradient-type reasoning method to properly determine the MAC regions; the latter employs max-min inference fuzzy logic to determine the access probabilities of users for enhancing dynamic TDMA efficiency under the QoS constraint. Simulation results show that the dynamic TDMA protocol with FTC can always guarantee the QoS requirement of real-time packet loss probability, regardless of the non-real-time traffic loads. Furthermore, it achieves higher system utilisation and less non-real-time packet delay compared to previously proposed PRMA, IPRMA and FRMA protocols.