The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper we present a new admission control (AC) for IEEE 802.16. The AC aims to accept new connections according to the negotiated service class (UGS, rtPS, nrTPS, and BE). To achieve this goal we propose to use the token bucket concept that provide QoS for real time traffics without degrading the QoS of non real time traffic. To show the benefit of the proposed AC, an analytical model based...
In cdma2000 1xEV, each mobile station determines its data rate based on a reverse activity bit (RAB) broadcasted by the base station and a set of up/down probabilities. In this paper, we propose a new rate control scheme that allows mobile stations to choose between two optimal rates determined by the rise over thermal (RoT) constraints. The base station determines the RAB signal based on the current...
Call Admission Control (CAC) schemes based on guard channel are widely used to protect handoff calls for seamless wireless services. In this paper, we propose a guard channel based CAC scheme where new calls arrive in batches. A fixed number of guard channels are reserved for handoff calls. The main objective of our proposed scheme is to alleviate the new call blocking probability due to guard channels...
Dynamic spectrum access is one of the most important premises of spectrum reuse based on cognitive radio technologies, which are considered to be the best way to alleviate the controversy on spectrum scarcity and low efficiency. However, most of previous work focuses on the increasing of system throughput, ignoring the QoS requirement of secondary users. In this paper, dynamic spectrum access with...
Proper admission control in cognitive radio networks is critical in providing QoS guarantees to secondary unlicensed users. In this paper, we study the admission control and channel allocation problem in overlay cognitive radio networks under the maximum cumulative delay constraint. We formulate it as a Markov decision process problem, and then solve it by transforming the original formulation into...
Quality communication over the wireless channel is now promised because of the advent of the broadband wireless. High speed data access is expected to be provided to subscribers through broadband wireless access. We propose a joint Call Admission Control (CAC) and Bandwidth Allocation (BA) for an IEEE 802.16 based WiMAX system. The presented schemes aim to provide QoS support along with a fair resource...
We propose a simple unified analytical model to analyze the IEEE 802.11 DCF infrastructure BSS performance in terms of MAC delay, PLR, and throughput efficiency under non-homogeneous and non-saturation conditions. Our model accounts for: (i) asymmetric traffic load between an AP and its associated STAs of an infrastructure BSS; (ii) transition from the non-saturation to saturation mode (and vice-versa)...
Cognitive radio network is expected to solve the spectrum scarcity by enabling unlicensed secondary users (SUs) to opportunistically utilize the licensed spectrum unused by primary users (PUs). In this paper, we propose an optimal admission control scheme which maximizes the profit while guaranteeing QoS of the PUs. The profit maximization problem is formulated as a Semi-Markov Decision Process (SMDP)...
In this paper, we propose an adaptive Call Admission Control for IEEE 802.16 scheduled flows. As the WiMAX defined services aim to adapt the bandwidth grant to the data rate of accepted sessions, a powerful CAC that takes into account flows characteristics and their heterogeneities must be used. Our proposal aims to take advantage of the variability of traffics and to adapt the CAC according to the...
In this paper, a novel call admission control (CAC) scheme for multicast and unicast integrated services is proposed, which optimizes service provision capacity for both services. A resource sharing model is presented in which multiple classes services are dynamically admitted into the system. Several basic CAC rules for the above resource model are proposed first and improved mechanisms are investigated...
In this paper, we propose an new admission control scheme jointly taking into account call-level QoS based on the dropping probability of handoff call and packet-level QoS based on the outage probability over threshold in IEEE 802.16e where user mobility is allowed and adaptive modulation and coding (AMC) is employed. The proposed admission control scheme is characterized by both a threshold for handoff...
Cognitive radio network is expected to solve the spectrum scarcity by enabling unlicensed secondary users (SUs) to opportunistically utilize the licensed spectrum unused by primary users (PUs). In this paper, we propose an optimal admission control scheme which maximizes the profit while guaranteeing QoS of the PUs. The profit maximization problem is formulated as a Semi-Markov Decision Process (SMDP)...
This paper defines a theoretical framework based on Markov Decision Processes (MDP) to deal with call control algorithms in links with variable capacity supporting multiple classes of service. The variable capacity problem, which arises in wireless network scenarios, is addressed by incorporating the link model into the MDP formulation and by introducing, beside the standard call admission policy,...
Dynamic spectrum access has become a promising approach to fully utilize the scarce spectrum resources. In this paper, two new dynamic spectrum access schemes for secondary users are proposed, which are based on continuous-time Markov chains (CTMC). Both the interactions between primary and secondary users and the effects of imperfect spectrum sensing(i.e. miss-detection and false alarm) are considered...
In this paper, we investigate the effects of pricing incentives in order to control the number of users requested access in cellular system. The system has been modeled as continuous time Markov chains with Poisson traffic for both new and handover calls. With mathematical results, formulations have been derived to show the values of new call blocking probability, probability of new calls are given...
This paper proposes an optimal CAC scheme in heterogeneous wireless networks called the GSMDP-based CAC (GCAC). Considering the limitations of the traditional Markov decision process for optimal CAC policy, we characterize the CAC problem through a GSMDP formulation. The performance is evaluated via simulation, and the results are compared with conventional GC scheme and an optimal CAC scheme based...
In this work, Call Admission Control Schemes which is one of the efficient resource management techniques are analyzed and proposed a new call admission scheme by using the structure of data allowing available bandwidth allocation over Complete-Partitioning Sharing technique. Voice calls are real-time services and needs fixed bandwidth, on the other hand, data calls are non-real time services and...
Random Early Detection (RED) is recommended as the congestion avoidance mechanism in packet switched networks in RFC2309 and has become the focus of much research into congestion control. Furthermore, RED and WRED are the AQM schemes most widely deployed in commercial Internet routers, such as Cisco and Juniper routers. This paper describes an analytical approach that models RED and WRED schemes using...
This paper studies the problem of congestion control and scheduling in ad hoc wireless networks that have to support a mixture of best-effort and real-time traffic. Optimization and stochastic network theory have been successful in designing architectures for fair resource allocation to meet long-term throughput demands. However, to the best of our knowledge, strict packet delay deadlines were not...
The IEEE 802.16 standard adopts a centralized resource-allocation mechanism to poll nodes with three polling modes, i.e., the unicast, multicast, and broadcast polling modes, depending on the residual bandwidth of the base station (BS). In the multicast and broadcast polling modes, the BS uses the truncated binary exponential backoff (TBEB) algorithm as the contention-resolution process (CRP) for...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.