Admission Control Scheme Research Articles

Call admission control for wireless mesh network based on power interference modeling using directional antenna

Interference is a fundamental issue in wireless mesh networks (WMNs) and it seriously affects the network performance. In this paper we characterize the power interference in IEEE 802.11 CSMA/CA based wireless mesh networks using directional antennas. A model based centralized call admission control (CAC) scheme is proposed which uses physical collision constraints, and transmitter-side, receiver-side and when-idle protocol collision prevention constraints. The CAC assists to manage requests from users depending on the available bandwidth in the network: when a new virtual link establishment request from a user is accepted into the network, resources such as interface, bandwidth, transmission power and channel are allocated in the participating nodes and released once the session is completed. The proposed CAC is also able to contain the interference in the WMN by managing the transmission power of nodes.

광 버스트 스위칭 네트워크에서 서비스 차별화를 제공하는 공유 기반의 허락 제어 방식

4 !(  !!#$%& ' 567,89:; ?@A ' ()(sharing) *+,-. /(admission control) 0 A BC9. B'()*+,-. /0 DE,FGH 67IJK&9L,MNO) 'PQ?'5RS (O7TDMNOU?'VWXY!!#$%& W Z[ )&]C67,:;@A^_C9. B'() *+,-. /0 `C!#$%*ab) 67,Lcde(throughput)f,gh&^F'*'Pijk(Markov) *+,lm_nA<?'5op<lmA\qC9. lmA]rsDMN,Nt@aDTDMNRsDMNOuv'VwGx(yzcsDMN,wG{|sDyz () 67,LO}AL~€x sDMN,wG{|‚2ƒhE&„Z'Vx )67,:Z(9†‡†x(ˆA8=9. AbstractIn this paper, sharing based admission control scheme is suggested for both service differentiation and improvement of wavelength utilization efficiency in burst switching networks. To provide service differentiation and high wavelength utilization efficiency, some of the wavelengths on a output link are shared with all classes and the others are used for the highest class exclusively. Markov based analysis is applied to the suggested scheme for the performance analysis and the numerical results are derived. The results are: The performance of lower traffic is more improved by the more number of shared wavelengths in case that the higher traffic or lower traffic is arrived equally or that the input rate of lower traffic is low. Another result is that the sharing effect of wavelengths is a little bit lowered when lower traffic passes the threshold. Keyword : sharing, service differentiation, optical burst switch, admission control, wavelength utilization

Teletraffic Analysis of a Call Admission Control Scheme with TCP Protocol Induced Factors

Teletraffic Analysis of a Call Admission Control Scheme with TCP Protocol Induced Factors

Joint resource allocation, routing and CAC for uplink OFDMA networks with cooperative relaying

In this paper, we propose a joint resource allocation, routing, and connection admission control (CAC) scheme for uplink transmission in orthogonal frequency division multiple access (OFDMA) relay networks with cooperative relaying. For cooperative relaying, relay station can relay uplink data from mobile station (MS) to base station with cooperation of the MS using transmit diversity. Transmit diversity can be achieved by virtual MISO via distributed space---time coding. The proposed scheme jointly allocates OFDMA resources and selects path for each user with CAC to maximize the upink throughput of cooperative OFDMA relay networks. The basic OFDMA resource unit is considered as a resource element which is one subcarrier over one OFDMA symbol. An efficient multi-choice multi-dimensional knapsack (MMKP) algorithm is presented for the proposed scheme. The proposed MMKP algorithm provides a unified framework which is applicable to OFDMA networks with and without cooperative relaying. We evaluate the performance of the proposed scheme with and without cooperative relaying in a hilly terrain with heavy tree density by using OPNET-based simulation. We show that the cooperative relaying improve the uplink system throughput compared with non-cooperative relaying, and the proposed scheme outperforms the conventional link quality-based scheme in both cooperative and non-cooperative relay networks.

Prioritized New Call Threshold Policy for Wireless Cellular Networks

This paper proposes a Prioritized New Call Threshold Policy for Call Admission Control schemes. It is known that connection reattempts negatively affect the system performance. In currently propose...

Handover Reduction via Joint Bandwidth Allocation and CAC in Randomly Distributed HCNs

For heterogeneous cellular networks (HCNs) with different cell size levels, the connection of high-mobility user equipment (UE) is a problem due to its short residence time in micro cell. In the former investigations, high-mobility UEs are always distributed to macro base stations (BSs) with reserved bandwidth, which is not an optimal solution to reduce handovers indeed. In this paper, a joint bandwidth allocation and call admission control (CAC) strategy is proposed to reduce handovers, that some high-mobility UEs are distributed to macro BSs for larger residence time, while the other high-mobility UEs are distributed to micro BSs for larger bandwidth. A scenario of randomly distributed HCNs with shared bandwidth and reserved bandwidth is considered. The joint bandwidth allocation and CAC problem is formulated based on the stochastic geometry modeling. A two-stage iteration method is given to obtain the optimal solutions. This work may shed some light for future extension and study.

Mobility-Prediction-Aware Bandwidth Reservation Scheme for Mobile Networks

Bandwidth is an extremely valuable and scarce resource in mobile networks; therefore, efficient mobility-aware bandwidth reservation is necessary to support multimedia applications (e.g., video streaming) that require quality of service (QoS). In this paper, we propose a distributed bandwidth reservation scheme called the mobility-prediction-aware bandwidth reservation (MPBR) scheme. The objective of MPBR is to reduce handoff call dropping rate and maintain acceptable new call blocking rate while providing efficient bandwidth utilization. MPBR consists of 1) a handoff time estimation (HTE) scheme that aims to estimate the time windows when a user will perform handoffs along the path to his destination, 2) an available bandwidth estimation (ABE) scheme that aims to estimate in advance available bandwidth, during the computed time windows in the cells to be traversed by the user to his destination, and 3) an efficient call admission control (ECaC) scheme that aims to control bandwidth allocation in the network cells. The simulation results show that MPBR outperforms existing schemes in terms of reducing handoff call dropping rate.

Performance Evaluation of Call Admission Control Schemes with New Call Reattempts in Wireless Cellular Networks

The majority of call admission control schemes proposed for wireless cellular networks do not take new call redials into account. However, connection reattempts are known to have a negative impact on the system performance because they generate more load. In this paper, we shall investigate how some popular call admission control schemes perform under more realistic conditions.

Load Balancing Early Handoff Scheme for Multimedia Data Transmission in Wireless Networks

This study developed a load balancing early handoff scheme that enables transfer part of heavy load in a base station to the others using the overlap between base stations in wireless cellular networks. The proposed scheme reduces the new call blocking probability (CBP) and handoff call connection dropping probability (CDP) as well as to increase the resource utilization of wireless networks. Since the scheme is triggered by a connection request received by the base station, it immediately reflects the loading of the base station. The proposed load balancing early handoff policy can be integrated in diverse call admission control schemes. The effectiveness of the load balancing early handoff scheme is demonstrated by integrating it with DMTBR to improve the call admission control function. Additionally, NS2 is used to simulate the load balancing early handoff scheme in a wireless network with wrap-around model. The simulation results show that the proposed scheme can effectively improve the wireless network resource utilization.

A reservation-based call admission control scheme and system modeling in 4G vehicular networks

Abstract In 4G cellular networks, call admission control (CAC) has a direct impact on quality of service (QoS) for individual connections and overall system efficiency. Reservation-based CAC schemes have been previously proposed for cellular networks where a certain amount of system bandwidth is reserved for high-priority calls, e.g., hand-off calls and real-time new calls. Traditional reservation-based schemes are not efficient for 4G vehicular networks, as the reserved bandwidth may not be utilized effectively in low hand-off rates. We propose a channel borrowing approach in which new best effort (BE) calls can borrow the reserved bandwidth for high-priority calls. Later, if a hand-off call arrives and all the channels are busy, it will pre-empt the service of a borrower BE call if there exists any. The pre-empted BE calls are kept in a queue and resume their service whenever a channel becomes available. The analytical model for this scheme is a mixed loss-queueing system for which it is difficult to calculate call blocking probability (CBP) and call dropping probability (CDP). Our focus in this paper is on the system modeling and performance evaluation of the proposed scheme. We present two system models that approximate the operation of the proposed scheme. For these models, we derive the CBP and CDP analytically. It is shown that our analytical results are very close to the ones obtained from simulations. Furthermore, it is observed that our channel borrowing approach decreases the CBP considerably while increases the CDP slightly over a large range of hand-off rates.

Priority Based Call Admission Control in Integrated 3G/WLAN Mixed Cell

Our objective is to propose an effective call admission control (CAC) scheme for Quality of service provisioning in heterogeneous networks (Integration of WLAN hotspots in 3G cell) .With the ubiquitous coverage of the cellular network and the disjoint deployment of WLANs in the hot-spot areas, the integrated system has a two-tier overlaying structure. The parameters have been taken into consideration is service type of user i.e. real and non-real service and also velocity of the user. For real time services which require higher Qos, has given preference to UMTS network and for non-real services , priority is given to WLAN network. The analytical model has been proposed for Priority based Call Admission Control (CAC) scheme and authenticates with simulation results followed by comparison with existing scheme. It is observed that there is an increase in the capacity of overall network marked by minimizing of two performance metrics – dropping probability of handoff calls and blocking probability of new calls. The importance of heterogeneous wireless network is essential to integrate 4G with WLAN to provide seamless roaming and user service connectivity. 4G is expected to provide high throughput, high data rate, low handoff Latency and reduce the power consumption of the mobile Node.

Performance Analysis of Preemption-Based Call Admission Scheme for Macrocell Users in Multi-Operator LTE Picocellular–Macrocellular Networks

A heterogeneous network (HetNet) is one of the core features that have been introduced in the LTE-advanced standardization to meet the predicted requirements for higher data rates and capacity. An integrated picocellular–macrocellular networks is part of such HetNets. Most previous works have concentrated on solving the picocellular–macrocellular networks challenges, including optimal picocell deployment, interference coordination, cell association methods and frequency resource allocations. However, the resource allocation control issue for LTE macrocells integrated with underlying picocells owned by different operators that can allow macrocell user (MU) accommodation has not been investigated deeply. Therefore, this paper proposes and analyzes a new resource allocation control framework called a preemption-based call admission control scheme (PCAC) for integrating independent underlying picocells with macrocell networks. The proposed scheme aims to utilize the resource blocks (RBs) of picocells efficiently to improve MU performance by allowing its MU visitors to utilize unused picocell RBs without any degradation for picocell users. A developed simulation model and a multi-dimensional continuous-time Markov chain (CTMC) model are used to model and analyze the proposed PCAC. The analytical model developed considers a limited-size buffer to store MUs, buffer time out and resource reservation. The MU connection-level performance metrics, including dropping and blocking probabilities, are derived and studied. The results indicate that better connection-level parameters for MUs and higher throughputs are achieved by using the proposed PCAC.

A QoS-Aware CAC with Bandwidth Reservation and Degradation Scheme in IEEE 802.16e Networks

Call admission control (CAC) schemes play a critical role in providing quality-of-service (QoS) guarantees for various classes of traffic with diverse QoS requirements in IEEE 802.16e networks. The dynamic CAC and bandwidth reservation scheme is one of the current schemes that simultaneously provides efficient utilization of network resources and guarantees QoS for admitted connections. However, its admission criteria starved high and low service classes due to its linear adaptation policy to accommodate more users into the network under moderate-to-heavy traffic load conditions. Its adaptive threshold for handoff connections is adjusted based on the arrival of new and handoff connections, that results in a waste of resources when the new and handoff connection arrival rate occurs frequently. In this paper, a new CAC scheme for Mobile WiMAX networks is proposed to prevent starvation of service classes and enhance the efficient utilization of network resources. The scheme determines a new admission criteria based on a scheduling service class. In the admission criteria, bandwidth degradation policy is used to admit more users when there is no available bandwidth to admit a more users. The adaptive threshold has been introduced dynamically to adjust the quantity of reserved bandwidth for handoff connections based on the traffic intensity of handoff requests. In addition, an analytical model for the proposed scheme is also developed. Extensive simulation experiments have been conducted to evaluate the performance of our proposed approach. The simulation results illustrate that the proposed scheme significantly improves the network efficiency compared to other schemes in terms of accepting more connections into the network and assuring QoS for all service classes. The numerical results have shown similar performance to the simulation results.

Robust Joint Transmit Beamforming With QoS Guarantees in Time-Asynchronous DAS

This paper studies the joint transmit beamforming optimization in the downlink of a single-cell multiuser distributed antenna system. Due to the distributed nature of transmit antennas, the signals received from different distributed antenna units (DAUs) will experience various transmission delays, and it is difficult to realize accurate symbol-level time synchronization at the user terminal. Thus, we turn to finding a robust joint transmit beamforming algorithm by replacing the received signal-to-interference-plus-noise ratio (SINR) with its lower-bound value. Moreover, the joint transmission incurs huge amount of data sharing among DAUs. Under the per-DAU maximum transmit power constraint, we aim to minimize the system backhaul overhead while satisfying the quality-of-service (QoS) requirement of each user. Since the backhaul overhead minimization requires the transmit beam vectors to have a group sparse structure and is NP-hard, we first make a convex relaxation and then apply the reweighted method to improve the sparsity of the beam vectors. Furthermore, an admission control scheme is applied to guarantee the feasibility of the problem, which iteratively removes the unsatisfied user with the worst quality of experience (QoE) away from the system. Simulation results show that our proposed robust algorithm can achieve a much better performance than the traditional nonrobust algorithm when time asynchronism is less than 30% of the symbol duration and can significantly reduce the system backhaul overhead by designing group sparse transmit beam vectors.

Performance Analysis of a Connection Admission Scheme for Future Networks

Future networks are to deliver any-traffic, anytime, anywhere with full quality of service (QoS) guarantees. They will evolve from typical heterogeneous networks (HetNets) into dense, organic, and irregular heterogeneous networks called DenseNets. They will be complex and face additional challenges of heterogeneity in many design dimensions like different radio access technologies (RAT's) shrinking in structure. Radio Resource Management (RRM) is one of the key challenges in providing for QoS for these networks. Connection Admission Control (CAC) scheme and intelligent scheduling techniques are employed on the links for RRM. In this paper a CAC scheme is developed that features multiple traffic classes, multiple admission parameters at both packet and connection level. The CAC scheme uses both signal to interference ratio (SIR) and delay as admission parameters since the single parameter based CAC algorithm is not adequate for the emerging traffic classes. The performance analysis of the model features Batch Markovian Arrival Process (BMAP) traffic, a better representative of the future traffic characteristics than the traditional Poisson traffic. A simple approximate Markovian analytical model is developed and used to analyze the complex network. The developed model with more admission parameters outperforms those with less admission control parameters for future networks traffic.

Impact of the routing protocol choice on the Envelope-Based Admission Control scheme for ad hoc networks

Envelope-Based Admission Control (EBAC) is an admission control scheme independent of the routing protocol, designed for ad hoc networks with the aim of supporting delay bounds. During the admission of users, EBAC evaluates a known route to determine whether it has enough bandwidth to support the new flow. To do this, the incoming node sends probing packets along a route so that the receiving node computes the envelope of the incoming flow, as well as the service envelope that models the service provided by the network. Based on these envelopes, the receiving node decides whether to admit the new flow. Admission control schemes that are decoupled from the routing protocol can work with any routing protocol. However, characteristics such as the way the underlying protocol deals with link failures or the speed of the route discovery process impact the admission control operation. This paper analyzes the performance of the EBAC scheme when used jointly with four different routing protocols: AODV, DSR, OLSR and DYMO. Results show that in both static and mobile scenarios, joint operation with the AODV protocol achieved the best performance of those evaluated.

Fuzzy call admission control combined with distributed dynamic channel assignment and reassignment for cellular mobile systems

In a cellular mobile system (CMS), the service area is divided into cells, each of which has numerous channels, which are shared by two types of call - new calls and handoff calls. Giving a higher priority to handoff calls than new calls is common practice. However, giving too much priority to handoff calls will result to excessive blocking of new calls. This work firstly proposes a distributed dynamic channel assignment and reassignment (DDCAR) scheme to satisfy three types of constraint - co-channel constraint (CCC), adjacent channel constraint (ACC), and co-site constraint (CSC), simultaneously. The purpose is to minimize the number of available channels that become unavailable for the assignment to new calls and to maximize the number of unavailable channels that become available for release when calls complete. To provide a higher priority to handoff calls, a fuzzy call admission control (FCAC) scheme, combined with the DDCAR, is proposed herein for implementation at the base station. A 7 × 7 CMS with two traffic patterns is employed as the test example. The test results reveal that the FCAC scheme significantly reduces the dropping probability of handoff calls at the cost of increasing the blocking probability of new calls to an acceptable level.

Throughput–Delay Tradeoff in Interference-Free Wireless Networks With Guaranteed Energy Efficiency

Existing works have addressed the tradeoffs between any two of the three performance metrics: throughput, energy efficiency (EE), and delay. In this paper, we unveil the intertwined relations among these three metrics under a unifying framework and particularly investigate the problem of EE-guaranteed throughput–delay tradeoff in interference-free wireless networks. We first propose two admission control schemes, referred to as the first-out and first-in schemes. We then formulate it as two stochastic optimization problems, aiming at throughput maximization (in the first-out scheme) or dropping rate minimization (in the first-in scheme) subject to requirement of EE (RoE), stability, admission control, and transmit power. To solve the problems, the EE-Guaranteed algorithm for throUghput-delAy tRaDeoff (eGuard), respectively called eGuard-I and eGuard-II in the first-out and first-in schemes, is devised. Moreover, with guaranteed RoE, we theoretically show that the eGuard (I and II) can not only push the throughput arbitrarily close to the optimal with tradeoffs in delay but also quantitatively control the throughput–delay performance on demand. Simulation results consolidate the theoretical analysis and particularly show the pros and cons of the two schemes.

Scheduling Dynamic Hard Real-Time Task Sets on Fully and Partially Reconfigurable Platforms

Reconfigurable systems are increasingly being employed in a large class of today's heterogeneous real-time embedded systems which often demand satisfaction of stringent timeliness constraints. However, executing a set of hard real-time applications on reconfigurable systems such that all timing constraints are satisfied while also allowing efficient resource utilization requires effective scheduling, mapping and admission control strategies. This letter presents methodologies for scheduling periodic hard real-time dynamic task sets on fully and partially reconfigurable field-programmable gate arrays (FPGAs). The floor of the FPGA is assumed to be statically equipartitioned into a set of homogeneous tiles (each of which act as individual processing elements or PEs) such that any arbitrary task of the given task set may be feasibly mapped into the area of a given tile. Experimental results reveal that the proposed algorithms are able to achieve high resource utilization with low task rejection rates over a variety of simulation scenarios.

Modulation Aware Connection Admission Control and Uplink Scheduling Algorithm for Wimax Networks

Mobile WiMAX standard defines air interface for mobile broadband wireless access (BWA) systems and aimed to provide high data rate with seamless mobility while maintaining the quality of service (QoS). However, QoS of real-time applications depends on the link quality, which necessitate the channel-aware connection admission control (CAC) and scheduling schemes. In this paper Modulation aware CAC scheme and base station (BS) uplink scheduling algorithm are proposed to improve the system capacity and QoS performance respectively. The proposed CAC scheme aims to increase the admission of higher priority real time services by degrading the bandwidth of admitted lower priority connections on the basis of their channel status without deteriorating their QoS performance much. The performances of proposed algorithms are evaluated through simulation by considering the metrics like throughput, delay and number of connections admitted.