Rozprawy doktorskie na temat „Call admission control”
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Ho, Chi-Jui. "Call admission control in cellular networks". Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/15730.
Pełny tekst źródłaDimitriou, Nikos. "Call admission control for multimedia CDMA". Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/930/.
Pełny tekst źródłaCheung, Michael. "Call admission control in wireless communications networks". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0016/NQ53488.pdf.
Pełny tekst źródłaNaghavi, Nika. "Call admission control in wireless mesh networks". Thesis, King's College London (University of London), 2017. https://kclpure.kcl.ac.uk/portal/en/theses/call-admission-control-in-wireless-mesh-networks(01d122ee-b6fe-4baa-b78c-9f5093136956).html.
Pełny tekst źródłaHossain, Firoz, i Abu-Shadat-Mohammad Sohab. "Mathematical Modelling of Call Admission Control in WCDMA Network". Thesis, Blekinge Tekniska Högskola, Avdelningen för signalbehandling, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2933.
Pełny tekst źródłaDe, Alwis Priyan Mihira. "Call admission control and resource utilization in WCDMA networks". Thesis, University of Canterbury. Electrical Engineering, 2005. http://hdl.handle.net/10092/9608.
Pełny tekst źródłaFoo, Yu Chiann. "Call admission control for high altitude platform station UMTS". Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/689/.
Pełny tekst źródłaLiu, Hui. "Dynamic call admission control under partial separation in ATM networks". Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/8975.
Pełny tekst źródłaSaintillan, Yves. "Performance evaluation of online call routing and admission control algorithms". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0005/MQ43558.pdf.
Pełny tekst źródłaYang, Xu. "Call admission control in wireless networks using a neuroevolution algorithm". Thesis, Queen Mary, University of London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515513.
Pełny tekst źródłaChevrollier, Nicolas. "Coexistence and call admission control in a heterogeneous wireless environment". Evry, Institut national des télécommunications, 2006. http://www.theses.fr/2006TELE0011.
Pełny tekst źródłaDans le monde digital qui nous entoure, différents types d'utilisateurs, d'applications et de technologies sans fil interagissent pour créer un environnement complexe et hétérogène. Le travail effectué dans cette thèse traite de problématiques introduites par le caractère hétérogène du monde digital. Le premier sujet d'étude s'attache à évaluer les interférences générées dans le bande de fréquence 2. 4 GHz lorsque plusieurs technologies sans fil opèrent en même temps dans un espace limité. Deux solutions sont proposées pour réduire ou éviter ces interférences. La première est un mécanisme d'ordonnancement des paquets au niveau de la couche MAC Bluetooth. La deuxième utilise des passages inter ou intra technologie déclenchés par des indicateurs de niveau 2. Le deuxième sujet d'étude s'attarde sur la mobilité verticale dans un environnement sans fil hétérogène. Les effets de cette mobilité sont évaluées sur le flux applicatif et la discontinuité de qualité de service que ces passages introduisent est analysée. Par la suite, deux algorithmes de contrôle d'admission qui prennent en compte le caractère néfaste de certains passages entre technologies sont proposés. Flexible et robuste, le premier repose sur une décision probabilistique d'admission dans une cellule WLAN. Le second utilise un système de réservation pondéré de bande passante et des passages préemptifs pour diminuer les nombres de passages de type "hard" et améliorer la qualité de service perçue par les utilisateurs
Ma, Zhongjing 1975. "Call admission control and routing control in integrated communication networks via dynamic programming". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82615.
Pełny tekst źródłaMansingh, Suhas. "Call admission control for leaky bucket regulated traffic in ATM networks". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0026/MQ51616.pdf.
Pełny tekst źródłaRamaswamy, Srinivasan. "Dynamic call admission control and quality-of-service regulation in ATM networks". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23061.pdf.
Pełny tekst źródłaZhang, Meng. "The impact of mobility on call admission control and scheduling in wireless networks /". View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202005%20ZHANGM.
Pełny tekst źródłaLevine, David A. "Resource allocation, call admission, and media access control protocols for wireless multimedia networks". Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/14766.
Pełny tekst źródłaLi, Bin. "Bandwidth allocation and call admission control in multi-services mobile wireless cellular networks /". View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202003%20LI.
Pełny tekst źródłaBates, Stephen. "Traffic characterisation and modelling for call admission control schemes on asynchronous transfer mode networks". Thesis, University of Edinburgh, 1997. http://hdl.handle.net/1842/1373.
Pełny tekst źródłaNi, Wenlong. "Optimal Call Admission Control Policies in Wireless Cellular Networks Using Semi Markov Decision Proces". University of Toledo / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1227028023.
Pełny tekst źródłaParvez, Asad. "Impact of actual interference on capacity and call admission control in a CDMA network". Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4496/.
Pełny tekst źródłaNi, Wenlong. "Optimal call admission control policies in wireless cellular networks using Semi Markov Decision Process /". Connect to full text in OhioLINK ETD Center, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1227028023.
Pełny tekst źródłaPhan, V. V. (Vinh V. ). "Smart packet access and call admission control for efficient resource management in advanced wireless networks". Doctoral thesis, University of Oulu, 2005. http://urn.fi/urn:isbn:9514276779.
Pełny tekst źródłaAhmed, Mohamed Hossam. "Capacity enhancement and performance analysis of call admission and load control in wireless communication networks". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60948.pdf.
Pełny tekst źródłaKeung, Yik. "Dynamic threshold call admission control policy of multi-service wireless cellular networks : a statistical approach /". View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202004%20KEUNG.
Pełny tekst źródłaIncludes bibliographical references (leaves 80-81). Also available in electronic version. Access restricted to campus users.
Tsai, Ming-Ying, i 蔡明穎. "Call Admission Control in ATM Networks". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/18121525023789473329.
Pełny tekst źródła國立交通大學
電信研究所
83
In this thesis, we mainly investigate the traffic control performed at the call setup phase in an ATM network loaded with heterogeneous sources. And this is what so called "Call Control". Under this topic, it is still divided into two categories:first, based on the numerical comparison results between the allowable number of connections from the exact analysis and that from the effective bandwidth method, here, we propose a new bandwidth allocation method for the call admission control to heterogeneous on-off sources in an infinite-buffer queueing system, which the network system accommodating the delay-tolerable but almost loss-free required sources. In the second part, we propose an optimum quantization scheme for the Markov-modulated sources in a bufferless fluid- flow model of an ATM network. Following the real-time computation algorithm for on-off sources proposed in \cite{duann}, with little modification, we extend the application to a more general source model, Markov-modulated sources. Furthermore, considering the quantization loss that might be caused under the computation algorithm in \cite{duann}, we suggest a policy for the sources to minimize the loss and achieve better utilization of link capacity.
Shi, YuFei. "ATM traffic generation and Call Admission Control". 1998. http://hdl.handle.net/1993/19409.
Pełny tekst źródłaCheng, Sheng-Wang, i 鄭昇旺. "Call Admission Control for Information Retrieval Service". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/70877032143772809821.
Pełny tekst źródła中華大學
資訊工程學系碩士班
93
The thesis is a research of call admission control (CAC) for information retrieval service. A CAC Model called "Constant Bit Rate and Port Based Bandwidth Reservation" (CBR-PBBR) was proposed in this thesis to guarantee the Quality of Service and try to enhance the performance of transmission. For the data flow to be transmitted on the architecture of Integrated Service or Differentiated Service, if the bandwidth request and the total size of the data flow are known, we can use the CAC Model of CBR-PBBR to transmit it. We hope this CAC model is to be efficient, economic and predictable on QOS. The model of CBR-PBBR will be suitable to the real time and interactive transmission. An example is VoIP. But the flows which with greatly variable request to bandwidth or unable to be restricted the transmission time will not be applicable. These flows need to be transformed into a constant bit rate transmission first if they can be. As for the non-real time or non-interactive Transmission, the model of CBR-PBBR still can be used because of the feature that transmission is easy to be transformed into a fixed size data flow. This is for the guarantee of QOS of SLA (service level agreement) or avoiding the network congestion. According to the discussion and simulation in the thesis, we can find the model of CBR-PBBR has better perfomance than UBR (non-CAC) transmission when the network is congested. In the points of average queue length, average transmission time to every packet and packet drop rate, the model of CBR-PBBR has good simulation result. Keywords : Call Admission Control, Bandwidth Reservation, CBR-PBBR, Quality of Service, Integrated Service, Differentiated Service
Lo, Yu-Shun, i 羅友舜. "Multicast Congestion Control Strategy based on Call Admission Control". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/50978700387936967876.
Pełny tekst źródła國立中正大學
通訊工程研究所
90
In Multicast Congestion Control research, “drop-to-zero” is a well-known problem. It means a slower receiver slows down faster receiver in the same multicast group. This is because the sender has to adapt its rate or window size to the slowest path, so that a multicast group performance could be dropped. In this paper, we propose that a call admission control (CAC) scheme manage receivers in multicast group to handle “drop-to-zero” problem and improve multicast performance. For this purpose, we integrate multicast congestion control protocol with CAC scheme and utilize the group member’s network information obtained from multicast congestion control protocol to calculate group reward. The basic idea is two-fold. First, the sender can observe the group performance in accordance with calculated group reward. Second, the sender can decide the permission that receiver ask for to join the multicast group in accordance with group reward. We expect to improve group performance and get better group reward and use simulation to analyze CAC scheme of group performance, member counts and group reward. We will show our CAC scheme can effectively drop slower receivers in multicast group and serve the majority of group receivers. The multicast group can build up the group performance and group reward to resolve “drop-to-zero” problem.
Lu, We-Ran, i 盧尉然. "Call Admission Control Scheme in Wireless Mobile Network". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/fd98ep.
Pełny tekst źródła銘傳大學
資訊傳播工程學系碩士班
92
The purpose of future telecommunications networks is to provide multiple services with together. To support various combined multiple services with quality of service (QoS) requirement in these wireless networks, the call admission control (CAC) plays an important role in resource management. We propose a novel call admission control scheme with buffer to guarantee QoS for both new calls and handoff calls. The queuing model is developed to estimate the threshold, which determines the channels dedicated to the handoff calls. In addition, the proposed scheme adopts the pseudo channel to improve the dropping rate of handoff calls, and employs a new mechanism to partially allocate channels for new calls when the channel occupancy is higher than threshold in order to refine the blocking rate. From the simulation, the proposed scheme significantly improves the dropping rate and the blocking rate in comparison with the existing methods
Tsai, Chi-lin, i 蔡其琳. "Utility-based Call Admission Control in Cellular Networks". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/97518327320338479568.
Pełny tekst źródła國立臺灣科技大學
電機工程系
102
The demand for cellular mobile services is rapidly growing. When the demand for bandwidth exceeds the supply, congestion will occur so that the QoS of users degrades and the revenue is reduced. Hence, it is important to use the limited bandwidth in the most efficient way. Call Admission Control (CAC) is a strategy to control the number of users into the networks to achieve congestion reduction. Nevertheless, only CAC cannot provide incentives to the users to use the network resources rationally and efficiently. One of the common approaches to deal with the problem is congestion pricing, where the behavior of users are affected by changing the charged price. In this work, we study how to maximize the utility by combining call admission control and congestion price in cellular networks. It is assumed that the utility is a function of the weighted blocking probability, which is a weighted sum of the new call blocking probability and the handoff failure probability. We consider two scenarios: single-cell and multi-cell. In single-cell scenarios, the handoff call arrival rate is assumed to be independent of the new call arrival rate. In multi-cell scenarios, the handoff call arrival rate depends on the new call arrival rate and other system parameters. On the other hand, the handoff call droppings are assumed to be less acceptable than new call blockings. Therefore, some guard channels may be reserved for handoff calls exclusively. We propose a utility-based CAC which adopts a higher congestion price when the channel occupancy exceeds a threshold. We derive the analytical models for the systems considered. An iterative algorithm is developed to find the steady state probability distribution and the performance measures of interest. The performance measures of interest are the new call blocking probability, the handoff failure probability, the give-up probability, the weighted blocking probability, the aggregate utility, and revenue. We study the effect of various system parameters on different performance measures. For comparison, we also present the performance of the traditional schemes with or without congestion price. Last but not least, the computer simulation is used to verify the accuracy of the analytical results.
Kevin i 劉文周. "A Call Admission Control Design for Transport Network". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/94515929656162805855.
Pełny tekst źródła國立清華大學
工業工程與工程管理學系
88
This thesis proposes a call admission control scheme based on a method of estimating cell loss quality for individual bursty traffic source. The estimate is expressed in terms of virtual cell lose probability for decreasing the influence of the optimization problems of the buffer size. The role of call admission control in high-speed networks is to maintain the network utilization at high level, while ensuring that the quality of service requirement of the individual calls are met. We use the term convolution call admission control to achieve the high level of network utilization by increasing the user connection numbers. Meanwhile we consider the Markov Decision Process﹙MDP﹚for developing the routing table. As we know the MDP will decide the available virtual path route that will maximize the expectation of networks revenue.
Chen, Yuon-Haan, i 陳詠翰. "Fuzzy Call Admission Control in a CDMA Cellular". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/22631464888768636198.
Pełny tekst źródła國立交通大學
電信工程系
88
Multiuser detection (MUD) is a very popular topic in recent years. Its impressive increase in capacity has caused that more and more latest wireless code division multiple access (CDMA) systems adopt this new technology. A lot of methods to implement the MUD were proposed and most of them tried to upgrade their performances and make them more feasible. The capacity limit, however, still exists due to other cells' multiple access interference (MAI) in a cellular system. As a result, a call admission control (CAC) scheme is required to control the number of voice users when using MUD. In this thesis, we first make a survey of the major types of MUDs and make comparisons among them, such as the important concepts, the performances, and the complexities, etc. Then we propose a fuzzy CAC using uplink MUD of successive interference cancellation (SIC), which has lower complexity and more advantages under the fading channel and imperfect power control. The fuzzy CAC considers both intra-cell and inter-cell MAI and it provides more accurate management of capacity than conventional (SIR-based) CAC in the CDMA cellular system.
Lai, Chich-Feng, i 賴志峰. "Fuzzy Call Admission Control for CDMA Cellular Systems". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/41798463949346212630.
Pełny tekst źródła國立中央大學
資訊工程研究所
88
Recently, the wireless personal communication system grows very fast and the CDMA has become the key technology for multiple accesses in the third generation wireless communication systems. Unlike conventional FDMA and TDMA systems, the capacity of CDMA is limited by the interference. Moreover, it is difficult to make call admission decisions under the wireless network conditions that are varying with the terrain and location. Therefore, a new call admission control policy is proposed to adapt to the changing network conditions for CDMA networks. Due to the fuzzy logic control has the capability to make decisions under ill-defined network environment, a call admission control policy using fuzzy logic control for CDMA networks is proposed in the thesis. The fuzzy rule set and the membership functions are obtained by using genetic algorithms to achieve the near-optimal solution. Simulation results show that, as the system load increases, the proposed CAC policy still can guarantee the dropping probability of handoff calls not beyond a pre-determined value and thus the quality of communications for handoff calls is offered.
Duann, Shii-Tyng, i 段喜亭. "A Call Admission Control Scheme for ATM Networks". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/23279709478319432340.
Pełny tekst źródła國立交通大學
電信研究所
81
This thesis proposes a new CAC scheme for ATM networks based on both long-term time averaged and instantaneous cell probabilities for global and individual bursty traffic The long-term time averaged cell loss probability is defined on a logically bufferless fluid flow traffic model. This investigates mainly the relation between bursty layer traffic cell loss probability. The overload period and underload period aggregated traffic are also discussed. Based on the model, relation between the average length of an underload period global cell loss probability is derived. The average length of underload period can also be used as a criterion for admission control because it is equivalent to global cell probability. In addition to long-term time averaged cell probability, we also analyze the instantaneous cell probability, considering the dynamic nature of the traffic, when a network is subject to an admission control. The proposed CAC procedure is divided into two sub-procedures. One called Preliminary CAC (PCAC) procedure designed based on long-term time averaged quality, another Advanced CAC (ACAC) procedure is designed based on quality. An on-line evaluation method is used to implement PCAC procedure, and a table look-up method is used to the ACAC procedure for real-time operation. The operation of proposed CAC scheme requires only two traffic parameters: peak and mean rates. The most important advantage the proposed procedure is that it can be performed in real time.
Wang, Wei-Tin, i 王偉廷. "IEEE 802.11e Performance Analysis and Call Admission Control". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/65878468373122836062.
Pełny tekst źródła國立成功大學
電腦與通信工程研究所
93
We investigate the performance of the emerging IEEE 802.11e standard by introducing a novel analytical model for the enhanced distributed coordination function (EDCF). The EDCF is modeled as a Markov chain which encapsulates AIFS (arbitrary inter-frame spacing), the minimum backoff window size, retry limit, freezing mechanism in backoff, different packet size. Saturation throughputs and saturation delays of different priority classes are derived based on the proposed model. The influences of different parameters like AIFS and packet size on the EDCF service differential schemes are demonstrated analytically. IEEE 802.11e EDCF aims at supporting relative service differentiation in the MAC layer. However, the backoff mechanism may cause huge packet delay and jitter. In order to guarantee quality of service for voice and video flows, we propose an ABR-QoS control scheme integrated with a measurement-based admission control scheme for the IEEE 802.11e enhanced distributed channel access. In the proposed admission control strategy, the access point makes bandwidth reservations according to individual real-time source’s requirement, while the ABR-QoS control mechanism based on a dynamic adjustment of the IEEE 802.11e EDCA parameters. The performances of the proposed scheme are extensively investigated by simulations. Simulation results show that, with the proposed ABR-QoS control and the admission control scheme, real-time multimedia traffic obtains great quality of service while the channel capacity is fully ultilized.
Sigwele, Tshiamo, Prashant Pillai i Yim Fun Hu. "Call admission control in cloud radio access networks". 2014. http://hdl.handle.net/10454/10791.
Pełny tekst źródłaOver the past decade, wireless communications has experienced tremendous growth, and this growth is likely to multiply in the near future. The proliferation of mobile users and an ever increasing demand for multimedia services has resulted in greater capacity requirements. Radio frequency spectrum is scarce and cannot meet this ever increasing demand and the required Quality of Service (QoS) will no longer be achieved if efficient Radio Resource Management (RRM) solutions are not found. Conventional Radio Access Networks (RAN) have standalone Base Stations (BS) with capacity preconfigured for peak loads. These RANs have high call blocking and dropping rates since BSs resources cannot be shared. Cloud based RANs (C-RAN) have been proposed as a cost and energy efficient way of meeting high capacity demand of future wireless access networks by consolidating BSs to the cloud. Instead of relying on rejection of new call requests due to limited BS resources, C-RAN takes benefit of the cloud elasticity, which allows dynamic provisioning of cloud BS resources. This paper presents a novel C-RAN Call Admission Control (C-RAN CAC) to ensure Grade of Service (GoS) by improving blocking probability and improvement of call waiting times. Call blocking probability, call average waiting time and system utilization are used to evaluate the performance of the proposed CAC algorithm.
Su-Chih, Kao, i 高蘇志. "Call Admission Control/Congestion Control in WCDMA with Bursty Multimedia Traffic". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/30893653808263610388.
Pełny tekst źródła國立臺灣科技大學
電機工程系
90
The third generation wireless communication system is expected to provide an efficient method that allows anybody to conduct multimedia communication in any place at any time. Different services usually have different transmission characteristics and quality of service requirements. Therefore, how to design an efficient media access control protocol is an important issue in terms of performance of wireless communication system. We consider wireless communication systems supporting video, voice and data services, where call admission control (CAC) is used to guarantee that existing and new connections can have enough resource to maintain QoS at the connection level; and congestion control is used to guarantee QoS at the packet level. The call admission control adopted in the thesis is a simple threshold scheme, i.e., the number of voice terminals in use can not exceed the threshold. The congestion control used is dynamic reservation assignment, and thus the capacity of real-time traffic and channel utilization can be improved. Via computer simulation, we make use of proper Markovian models for studying the performance measures of video traffic and voice traffic respectively, and studying the data average message delay of data traffic with different data message arrival process, e.g., Poisson message arrival process and self-similar message arrival process. We also study the effects of different system parameter on video packet loss probability, voice packet loss probability, voice call blocking probability, and data average message delay.
Chen, Tsung-Chin, i 陳宗群. "A Ratio-Based Call Admission Control for ATM networks". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/18458921551342480773.
Pełny tekst źródła國立中山大學
電機工程學系研究所
89
We propose a novel call admission control which makes use of ratio-based traffic measurement to estimate the required bandwidth when a new call is issued. Existing approaches fail to estimate properly the required bandwidth. To alleviate the problem, we calculate the ratio between the measured mean rate and the mean rate declared by UPC parameters. The ratio and the target cell loss rate are used to estimate the required bandwidth to make decision if a new call is accepted or rejected. Because of more accurate estimation of required bandwidth, our method can provide a better control on quality of service.
Hung-Erh, Huang, i 黃宏二. "A Study of Wireless Dynamic Call Admission Control Mechanism". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/10933613392825547657.
Pełny tekst źródła國防管理學院
國防資訊研究所
91
Abstract In the field of wireless mobile communication, the performance of base stations is crucial to the quality of communication, the quality of service for base stations will be measured by the new calls block rate and hand off calls drop rate. When the integral demand of the base stations is greater than the total channel span, hand off calls and new calls will not be available due to the congestion of base stations. Therefore, the kernel of the question lies in the efficiency of utilizing the precious channel resources. This research has set its goal on raising the frequency in using the channels of base stations through “Call Admission Control” (CAC). From the view point of the distribution of channel resources, we categorize the wireless communication environment into two approaches, namely “Fixed Channel Allocation” and “Dynamic Channel Allocation”. Then we introduce the “Setting In Advance” and “Random Early Detection Mechanism” respectively into these two approaches to simulate the operations of the base stations. From the result of simulation, both the cut off rate of new calls and that of the hand off calls, we can compare these two mechanisms and thus raise the performance of the base stations.
Chung, Yu-Fen, i 鍾玉芬. "Call Admission Control with Neural network in ATM networks". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/84887464996173855331.
Pełny tekst źródła義守大學
資訊工程學系
89
Asynchronous Transfer Mode (ATM) netowrks is an essential technology for integrating multimedia services in high-speed networks and recommended by International Telecommunications Union (ITU) for broadband integrated services digital networks (B-ISDN). It provides different quality of services (QoS) for different types of traffic sources with widely varying traffic characteristics. In order to guarantee the QoS requirements and to achieve high network utilization, it is necessary to implement a call admission controller. In this thesis, we investigate a CAC algorithm with neural network first. Owing to the self-learning capacity, the neural networks can be trained to fit the uncertainty of the traffic source. However, increasing the inputs result in increasing the complexity of the neural network. We think that different types of inputs can be processed separately, such as network status and traffic characteristics. Therefore, we increase the inputs of neural networks to promote its ability. Secondly, we propose a CAC scheme with two algorithms, named B&WCAC. In many literatures, they always apply only one algorithm to implement CAC. In ATM networks, we think it can adopt more than one algorithm to implement CAC scheme according to different types of traffic sources. We expect that it can be more precise and efficient for CAC by dividing traffic sources and algorithms into two types, black and white.
Yeh, Chih-Hsiang. "Call Admission Control for VoIP in IEEE 802.11 WLANs". 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-3008200714485700.
Pełny tekst źródłaYeh, Chih-Hsiang, i 葉志祥. "Call Admission Control for VoIP in IEEE 802.11 WLANs". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/78164127982022930515.
Pełny tekst źródła臺灣大學
電機工程學研究所
95
Voice over Internet Protocol (VoIP) is no longer only feasible in wired networks, but also applicable through wireless networks as prevalence of wireless networks grows with the technology maturity and rising demand. While making a VoIP call over WiFi wireless networks is applicable, this is not a service with guaranteed quality. With limited bandwidth, an overloaded AP may cause wireless users to experience delayed packets, high packet loss rate, and even low throughput. IEEE 802.11 wireless Local Area Network (WLAN) was originally designed only for data traffic transmission, and therefore deficiency in real-time traffic transmission, such as VoIP applications, is inevitable. Not being able to timely transmit real-time packets not only fails to meet the demand of users, but also increases unnecessary loading in the wireless network. Industries and academies have made lots of efforts on providing QoS for real-time voice traffic which usually coexists with other classes of traffic. In this thesis, a call admission control mechanism is proposed which not only timely monitors the wireless networks, but also dynamically adjusts the number of admissible clients to wireless networks. New VoIP users not only know the network condition before entering it, but also accurately predict transmission quality through sending probing packets. With the mechanism, existing VoIP users in the wireless networks have their service protected, and potential VoIP users can expect good quality of service once admitted.
Chien-An, Chen. "Multi-Criteria Call Admission Control in IEEE 802.11 WLAN for Multi-Criteria Call Admission Control in IEEE 802.11 WLAN for Distributed Access Point Selection". 2004. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0009-0112200611284515.
Pełny tekst źródłaChiu, Chin-Lien, i 邱進連. "Joint call admission control/congestion control for wireless integrated voice/data networks". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/53527107919468149937.
Pełny tekst źródła國立臺灣科技大學
電機工程系
89
The next generation wireless personal communication is expected to provide an efficient method that allows anybody to conduct multimedia communication in any place at any time. Different traffics usually have different transmission characteristics and quality of service requirements. Therefore, how to design an efficient media access control protocol is an important issue in terms of performance of wireless communication system. We consider wireless communication systems supporting both voice and data services, where call admission control (CAC) is used to guarantee that existing and new connections can have enough resource to maintain QoS at the connection level; and congestion control is used to guarantee QoS at the cell level. The call admission control adopted in the thesis is a simple threshold scheme, i.e., the number of voice terminals in use can not exceed the threshold. The congestion control used is D-TDMA/PRPTS, where data request packets can be transmitted in a minislot only if no voice request packets have already started at the same minislot. Therefore, collisions between voice request packets and data request packets can be avoided, the voice packet loss probability is reduced, and thus the capacity of voice terminals and channel utilization can be improved. Furthermore, to avoid excessive delay due to minislot contention, voice request packet is dropped if it can not succeed in the frame at which it originates. We study the effect of voice interarrival time and voice threshold on voice packet loss probability, voice call blocking probability, data packet average delay, and channel utilization. With a Markovian model, the voice packet loss probability, voice blocking probability and channel utilization of voice traffics are derived, and the analytical results are verified with the simulation results. Due to the mathematical complexity, for integrated voice/data scenarios, computer simulation is used to evaluate the effect of proposed CAC and congestion control on the performance measures of both voice and data traffics.
Ramlakhan, Niven Bhimraj. "Downlink call admission control in mixed service CDMA cellular networks". Thesis, 2007. http://hdl.handle.net/10413/8990.
Pełny tekst źródłaThesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2007.
Jia-Ci, He, i 何嘉奇. "Call Admission Control with Restriction and Degradation in Wireless Networks". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/37668246141601999930.
Pełny tekst źródła國立臺灣科技大學
電機工程系
93
It is expected that various kinds of services, e.g., voice, video, multimedia data, etc., will be provided in the next generation of mobile/wireless communication systems. For multimedia traffic to be supported successfully over wireless links, it is necessary to provide quality of service (QoS) guarantees between the end-systems in wireless networks. We propose a call admission control with restriction and degradation (CAC-RD) for wireless networks which uses adaptive bandwidth allocation to provide users multi-level QoS. We derive the associated analytical model and the expressions for new call blocking probability, handoff failure probability, and average bandwidth. Due to mathematical complexity, degradation ratio and upgrade/degrade frequency are found via computer simulation. The simulation program is written in C language not only to verify the accuracy the analytical results but also to understand and control the details of various CAC schemes. It is shown that the analytical results are in reasonable agreement with simulation results, especially when the offered load is light. For comparison purposes, the model for CAC with restriction but no degradation (CAC-R) is also shown. It is shown that, with service degradation (CAC-RD), the new call blocking probability and handoff failure probability are smaller than those without service degradation (CAC-R). The effects of restriction threshold, traffic mix and call holding time on performance measures are also studied. It is concluded that CAC for wireless networks should take into account the offered load, traffic mix, and the call holding time in order to satisfy all required QoS requirements.
Liu, Cheng-Tse, i 劉政澤. "Optimization on Call Admission Control in Multiple-Service Wireless Networks". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/ar23a8.
Pełny tekst źródła國立交通大學
電信工程系所
92
With the third-generation mobile phone system coming, it provides multiple-service by higher transmission rate. Since wireless resources are limited, how to allocate the bandwidth is interesting. That is, call admission control is considerable. If we want to minimize the system cost, what can we do? In this thesis, we model channels by Markov chains and find the optimal policy based on Markov decision process. In single service network, the Guard Channel policy is the optimal policy. We will modify it for multiple-service networks, then use this policy to do one-step policy improvement. The next policy is near to the optimal policy.
Wu, Chen-Feng, i 吳振鋒. "Prediction-Based Call Admission Control Schemes for Wireless Cellular Networks". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/39590136584552354323.
Pełny tekst źródła大同大學
資訊工程學系(所)
95
Due to the rapid progression for wireless technology, the cellular networks are also evolved from the first generation to the third generation and even beyond the third generation further. The subscriber services are gradually changed from voice to multimedia since higher speed of transmission will be provided by newer cellular technologies. Consequently, the multimedia services are getting to become the major trend in next-generation cellular networks, and the Call admission control (CAC) will play the key role for guaranteeing the quality of service (QoS) in wireless cellular networks, owing to the scarce wireless spectrum. Because the user mobility is so indeterminate, the goal which keeps both call dropping probability (CDP) and call blocking probability (CBP) below a lower level simultaneously is more difficult and seldom literatures were focused on such issue. Thus, the appropriate prediction information will be useful for a CAC scheme to meet QoS issues of both CDP and CBP at the same time. There have been so many studies focusing on the prediction of user mobility, and they are fallen into two considerations: the cell approach consists in recording handoff statistics on each cell each time; the user approach consists in computing a roaming profile for each user and recording each visited cell during a call. The design issues of a CAC should be also considered in different scenarios by the same token. Moreover, it will be an important issue for the operation of cellular networks to integrate CAC scheme with the prediction of user mobility produced according to the demand of real situation. In terms of prediction of user mobility, two CAC schemes that are coupled with different prediction methods are proposed in this dissertation. Upon actually using scenarios that may be geography constraint, possession constraint of individual information, and so on, two prediction methods for user mobility are proposed simultaneously. For user approach, the Hidden Markov Models (HMM) concept which is suitable for solving a dynamic situation is applied to predict user mobility then provides information for the correspondingly proposed CAC scheme, and the time series prediction which can predict most information, such as system utilization and CDP, is combined with the correspondingly proposed CAC scheme for cell approach. The SMPL (SiMulation Programming Language) has been adopted for the simulation to evaluate the performance of the proposed schemes. The simulation results of both user and cell approaches show that the proposed CAC schemes are superior to the traditional guard channel schemes in terms of CDP and CBP, and better utilization can be also achieved by the proposed schemes. Indeed, according to the simulation results, the proposed CAC schemes that are combined with the appropriate prediction method of user mobility can do some contributions on wireless cellular networks.
He, Jia-ci, i 何嘉奇. "Call Admission Control with Restriction and Degradation in Wireless Networks". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/31260814022936206084.
Pełny tekst źródła國立臺灣科技大學
電機工程系
93
It is expected that various kinds of services, e.g., voice, video, multimedia data,etc., will be provided in the next generation of mobile/wireless communication systems. For multimedia traffic to be supported successfully over wireless links, it is necessary to provide quality of service (QoS) guarantees between the end-systems in wireless networks. We propose a call admission control with restriction and degradation (CAC-RD) for wireless networks which uses adaptive bandwidth allocation to provide users multi-level QoS. We derive the associated analytical model and the expressions for new call blocking probability, handoff failure probability, and average bandwidth. Due to mathematical complexity, degradation ratio and upgrade/degrade frequency are found via computer simulation. The simulation program is written in C language not only to verify the accuracy the analytical results but also to understand and control the details of various CAC schemes. It is shown that the analytical results are in reasonable agreement with simulation results, especially when the offered load is light. For comparison purposes, the model for CAC with restriction but no degradation (CAC-R) is also shown. It is shown that, with service degradation (CAC-RD), the new call blocking probability and handoff failure probability are smaller than those without service degradation (CAC-R). The effects of restriction threshold, traffic mix and call holding time on performance measures are also studied. It is concluded that CAC for wireless networks should take into account the offered load, traffic mix, and the call holding time in order to satisfy all required QoS requirements.
Hunag, Chin-yin, i 黃金崟. "Analysis of Call Admission Control of Multirate Cognitive Radio Networks". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/98729080305363107687.
Pełny tekst źródła國立臺灣科技大學
電機工程系
101
In the past few years, the technology of cognitive radios has captured the attention of many researchers in that it promises an effective way of enhancing spectrum usage and solving the problem of heterogeneity of radio devices. We study the multirate cognitive radio networks where the users of each class have a different bandwidth requirement. There are one class of primary users, PU, and two classes of secondary users, SU1, and SU2. We consider two call admission control policies: CAC1 and CAC2, where PU new calls have the preemptive priority over ongoing SU1 and SU2 calls, and some sub-channels are reserved for SU1 against SU2 new calls. Furthermore, under CAC1, SU1 handoff calls can preempt SU2 ongoing calls, whereas under CAC2, SU1 handoff calls cannot preempt SU2 ongoing calls. The system can be modeled as a three-dimensional Markov process. We propose an iterative algorithm to find the steady state probability distribution and compute the performance measures. The performance measures of interest are new call blocking probability, forced termination probability, and throughput. With the same system parameters, first, it is shown that the new call blocking probabilities of PU, SU1, and SU2 calls remain the same no matter CAC1 or CAC2 is enforced. Second, the forced termination probability of SU1 calls is lower than that of SU2 calls under CAC1, except for small PU service rates or large SU2 service rates. The forced termination probability of SU1 calls is higher than that of SU2 calls under CAC2, except for large SU1 service rates or small SU2 service rates. Third, the throughput of SU1 (SU2) calls remains almost the same no matter CAC1 or CAC2 is enforced. The throughput of SU1 calls is higher than that of SU2 calls except for small SU1 arrival rates. Last but not least, we verify the accuracy of the analytical results by the simulation program written by visual C++. In most cases studied, the analytical results are reasonably close to the simulation results.