Admission control in time-slotted multihop mobile networks

The emergence of nomadic applications have generated a lot of interest in next-generation wireless network infrastructures which provide differentiated service classes. So it is important to study how the quality of service (QoS), such as packet loss and bandwidth, should be guaranteed. To accomplish this, we develop am admission control scheme which can guarantee bandwidth for real-time applications in multihop mobile networks. In our scheme, a host need not discover and maintain any information of the network resources status on the routes to another host until a connection request is generated for the communication between the two hosts, unless the former host is offering its services as an intermediate forwarding station to maintain connectivity between two other hosts. This bandwidth guarantee feature is important for a mobile network to interconnect wired networks with QoS support. Our connection admission control scheme can also work in a stand-alone mobile ad hoc network for real-time applications. This control scheme contains end-to-end bandwidth calculation and bandwidth allocation. Under such a scheme, the source is informed of the bandwidth and QoS available to any destination in the mobile network. This knowledge enables the establishment of QoS connections within the mobile network and the efficient support of real time applications. In the case of ATM interconnection, the bandwidth information can be used to carry out an intelligent handoff between ATM gateways and/or to extend the ATM virtual circuit service to the mobile network with possible renegotiation of QoS parameters at the gateway. We examine via simulation the system performance in various QoS traffic flows and mobility environments     

QoS routing in ad hoc wireless networks

The emergence of nomadic applications have generated much interest in wireless network infrastructures that support real-time communications. We propose a bandwidth routing protocol for quality-of-service (QoS) support in a multihop mobile network. The QoS routing feature is important for a mobile network to interconnect wired networks with QoS support (e.g., ATM, Internet, etc.). The QoS routing protocol can also work in a stand-alone multihop mobile network for real-time applications. This QoS routing protocol contains end-to-end bandwidth calculation and bandwidth allocation. Under such a routing protocol, the source (or the ATM gateway) is informed of the bandwidth and QoS available to any destination in the mobile network. This knowledge enables the establishment of QoS connections within the mobile network and the efficient support of real-time applications. In addition, it enables more efficient call admission control. In the case of ATM interconnection, the bandwidth information can be used to carry out intelligent handoff between ATM gateways and/or to extend the ATM virtual circuit (VC) service to the mobile network with possible renegotiation of QoS parameters at the gateway. We examine the system performance in various QoS traffic flows and mobility environments via simulation. Simulation results suggest distinct performance advantages of our protocol that calculates the bandwidth information. It is particularly useful in call admission control. Furthermore, “standby” routing enhances the performance in the mobile environment. Simulation experiments show this improvement     

An FDD wideband CDMA MAC protocol with minimum-power allocation and GPS-scheduling for wireless wide area multimedia networks

A frequency division duplex (FDD) wideband code division multiple access (CDMA) medium access control (MAC) protocol is developed for wireless wide area multimedia networks. In order to reach the maximum system capacity and guarantee the heterogeneous bit error rates (BERs) of multimedia traffic, a minimum-power allocation algorithm is first derived, where both multicode (MC) and orthogonal variable spreading factor (OVSF) transmissions are assumed. Based on the minimum-power allocation algorithm, a multimedia wideband CDMA generalized processor sharing (GPS) scheduling scheme is proposed. It provides fair queueing to multimedia traffic with different QoS constraints. It also takes into account the limited number of code channels for each user and the variable system capacity due to interference experienced by users in a CDMA network. To control the admission of real-time connections, a connection admission control (CAC) scheme is proposed, in which the effective bandwidth admission region is derived based on the minimum-power allocation algorithm. With the proposed resource management algorithms, the MAC protocol significantly increases system throughput, guarantees BER, and improves QoS metrics of multimedia traffic.     

一种基于对策模型的ATM网络连接接纳控制策略

本文先简述了ATM网络进行连接接纳控制(Connection Admission Control:CAC)的主要方法,其中主要综述了基于动态带宽分配的CAC策略,而后从合作对策模型的角度讨论业务间共享链路资源的公平性问题,提出一种基于时延带宽积的业务收益函数形式,并通过遗传算法求解待优化的对策函数,以决定对呼叫请求的接入或拒绝。仿真结果表明此方法能够更好地保证不同带宽和服务质量要求的业务共享网络资源的公平性。     

A connection admission control scheme based on game theoretical model in ATM networks

In this paper, the main schemes of connection admission control (CAC) in ATM networks are briefly discussed especially the principle of dynamic bandwidth allocation. Then the fair share of the bandwidth among different traffic sources is analyzed based on cooperative game model. A CAC scheme is proposed using the genetic algorithm (GA) to optimize the bandwidth-delay-product formed utilization function that ensures the fair share and accuracy of accepting/rejecting the incoming calls. Simulation results show that the proposed scheme ensures fairness of the shared bandwidth to different traffic sources.     

Bandwidth allocation and admission control in ATM networks withservice separation

The statistical multiplexing operation within an ATM network node is considered, with respect to different methods for the allocation of the bandwidth of an outgoing link. Service separation is assumed by dividing the overall traffic flows into classes, homogeneous in terms of performance requirements and statistical characteristics. Which share the bandwidth of a link according to some specified policy. This context allows one to clearly define, by means of several existing approaches, a region in the space of connections of the different classes (call space) where quality of service (QoS) requirements at the cell level are satisfied. Within this region, some criteria for allocating the bandwidth of the link to the service classes are proposed, and the resulting allocation and call admission control (CAC) strategies are defined and analyzed. The goal of these operations is to achieve some desired QoS at the call level. Several numerical simulation results are presented, in order to highlight the different performance characteristics of the various methods     

A Noncooperative Game-Theoretic Framework for Radio Resource Management in 4G Heterogeneous Wireless Access Networks

Fourth generation (4G) wireless networks will provide high-bandwidth connectivity with quality-of-service (QoS) support to mobile users in a seamless manner. In such a scenario, a mobile user will be able to connect to different wireless access networks such as a wireless metropolitan area network (WMAN), a cellular network, and a wireless local area network (WLAN) simultaneously. We present a game-theoretic framework for radio resource management (that is, bandwidth allocation and admission control) in such a heterogeneous wireless access environment. First, a noncooperative game is used to obtain the bandwidth allocations to a service area from the different access networks available in that service area (on a long-term basis). The Nash equilibrium for this game gives the optimal allocation which maximizes the utilities of all the connections in the network (that is, in all of the service areas). Second, based on the obtained bandwidth allocation, to prioritize vertical and horizontal handoff connections over new connections, a bargaining game is formulated to obtain the capacity reservation thresholds so that the connection-level QoS requirements can be satisfied for the different types of connections (on a long-term basis). Third, we formulate a noncooperative game to obtain the amount of bandwidth allocated to an arriving connection (in a service area) by the different access networks (on a short-term basis). Based on the allocated bandwidth and the capacity reservation thresholds, an admission control is used to limit the number of ongoing connections so that the QoS performances are maintained at the target level for the different types of connections.     

Simulation analyses of weighted fair bandwidth‐on‐demand (WFBoD) process for broadband multimedia geostationary satellite systems

Advanced resource management schemes are required for broadband multimedia satellite networks to provide efficient and fair resource allocation while delivering guaranteed quality of service (QoS) to a potentially very large number of users. Such resource management schemes must provide well‐defined service segregation to the different traffic flows of the satellite network, and they must be integrated with some connection admission control (CAC) process at least for the flows requiring QoS guarantees. Weighted fair bandwidth‐on‐demand (WFBoD) is a resource management process for broadband multimedia geostationary (GEO) satellite systems that provides fair and efficient resource allocation coupled with a well‐defined MAC‐level QoS framework (compatible with ATM and IP QoS frameworks) and a multi‐level service segregation to a large number of users with diverse characteristics. WFBoD is also integrated with the CAC process. In this paper, we analyse via extensive simulations the WFBoD process in a bent‐pipe satellite network. Our results show that WFBoD can be used to provide guaranteed QoS for both non‐real‐time and real‐time variable bit rate (VBR) flows. Our results also show how to choose the main parameters of the WFBoD process depending on the system parameters and on the traffic characteristics of the flows. Copyright © 2005 John Wiley & Sons, Ltd.     

A Novel Probability-Based Handoff Strategy for Multimedia LEO Satellite Communications

A novel bandwidth allocation strategy and a connection admission control technique arc proposed to improve the utilization of network resource and provide the network with better quality of service （QoS） guarantees in multimedia low earth orbit （LEO） satellite networks. Our connection admission control scheme, we call the probability based dynamic channel reservation strategy （PDR）, dynamically reserves bandwidth for real-time services based on their handoff probability. And the reserved bandwidth for real-time handoff connection can also be used by new connections under a certain probability determined by the mobility characteristics and bandwidth usage of the system. Simulation results show that our scheme not only lowers the call dropping probability （CDP） for Class I real-time service but also maintains the call blocking probability （CBP） to certain degree. Consequently, the scheme can offer very low CDP for rcal-time connections while keeping resource utilization high.     

Dynamic reservation TDMA protocol for wireless ATM networks

A dynamic reservation time division multiple access (DR-TDMA) control protocol that extends the capabilities of asynchronous transfer mode (ATM) networks over the wireless channel is proposed in this paper. DR-TDMA combines the advantages of distributed access and centralized control for transporting constant bit rate (CBR), variable bit rate (VBR), and available bit rate (ABR) traffic efficiently over a wireless channel. The contention slots access for reservation requests is governed by the framed pseudo-Bayesian priority (FPBP) Aloha protocol that provides different access priorities to the control packets in order to improve the quality-of-service (QoS) offered to time sensitive connections. DR-TDMA also features a novel integrated resource allocation algorithm that efficiently schedules terminals' reserved access to the wireless ATM channel by considering their requested bandwidth and QoS. Integration of CBR, voice, VBR, data, and control traffic over the wireless ATM channel using the proposed DR-TDMA protocol is considered in this paper. Simulation results are presented to show that the protocol respects the required QoS of each traffic category while providing a highly efficient utilization of approximately 96% for the wireless ATM channel     

QoS Performance Bounds and Efficient Connection Admission Control for Heterogeneous Services in Wireless Cellular Networks

Quality-of-Service (QoS) performance and connection admission control (CAC) for heterogeneous services in wireless multiple access networks are investigated. The heterogeneous services include constant bit rate (CBR), variable bit rate (VBR) and available bit rate (ABR) services. Multiple access control is handled by a polling-based scheme with non-preemptive priority. Tight delay variation (jitter) bounds for CBR connections and delay bounds for VBR connections are derived. A CAC scheme based on the derived bounds is developed. The CAC makes use of user mobility information to reserve an appropriate amount of system resources for potential handoff connections to achieve low handoff connection dropping rate (HCDR). Simulation results show that the proposed CAC scheme can achieve both low HCDR and high resource utilization.     

Training techniques for neural network applications in ATM

The main problems of adaptive ATM quality of service (QoS) control methods using neural networks were the exponentially wide range of the output target and the real-time training data sampling. But new practical techniques to overcome these problems may open new neural network applications. In this article, the framework of connection admission control (CAC) is described as a typical example of neural-network-based QoS estimation and two practical techniques, called relative target method and virtual output buffer method, are presented to enhance the neural network performance in CAC     

Adaptive bandwidth management in ATM networks

A framework for adaptive bandwidth management in ATM based networks is proposed. It is based on a layered approach which includes bandwidth allocation to virtual networks. The central concept of this approach is adaptive estimation of the effective bandwidth required, by connections carried in the network. To achieve reliable results the estimation process takes into account both the traffic source declarations and the connection superposition process measurements on the network links. This is done in an optimization framework provided by estimation theory. A study, based on a linear two-state Kalman filter, shows that the proposed approach provides good adaptation to undeclared changes in traffic parameters and that the network performance is significantly improved when compared to the effective bandwidth allocation based solely on the source parameters declarations. These features allow more relaxed source parameter declarations and at the same time permit less stringent source policing. Thus the two bottlenecks influencing bandwidth management in ATM networks can be significantly widened.     

Multiple access control with intelligent bandwidth allocation forwireless ATM networks

Two major challenges pertaining to wireless asynchronous transfer mode (ATM) networks are the design of multiple access control (MAC), and dynamic bandwidth allocation. While the former draws more attention, the latter has been considered nontrivial and remains mostly unresolved. We propose a new intelligent multiple access control system (IMACS) which includes a versatile MAC scheme augmented with dynamic bandwidth allocation, for wireless ATM networks. IMACS supports four types of traffic-CBR, VBR, ABR, and signaling control (SCR). It aims to efficiently satisfy their diverse quality-of-service (QoS) requirements while retaining maximal network throughput. IMACS is composed of three components: multiple access controller (MACER), traffic estimator/predictor (TEP), and intelligent bandwidth allocator (IBA). MACER employs a hybrid-mode TDMA scheme, in which its contention access is based on a new dynamic-tree-splitting (DTS) collision resolution algorithm parameterized by an optimal splitting depth (SD). TEP performs periodic estimation and on-line prediction of ABR self-similar traffic characteristics based on wavelet analysis and a neural-fuzzy technique. IBA is responsible for static bandwidth allocation for CBR/VBR traffic following a closed-form formula. In cooperation with TEP, IBA governs dynamic bandwidth allocation for ABR/SCR traffic through determining the optimal SD. The optimal SDs under various traffic conditions are postulated via experimental results, and then off-line constructed using a back propagation neural network (BPNN), being used on-line by IBA. Consequently, with dynamic bandwidth allocation, IMACS offers various QoS guarantees and maximizes network throughput irrelevant to traffic variation     

A real-time dynamic connection admission controller based ontraffic modeling, measurement, and fuzzy logic control

Broadband networks based on asynchronous transfer mode (ATM) have to support traffic with widely different traffic characteristics and quality of service requirement. In this paper, we extend our earlier work in and develop a dynamic connection admission controller (CAC) that supports cell loss requirements. The CAC algorithm explicitly computes the equivalent bandwidth required to support each class of connections based on on-line observations of aggregate traffic statistics as well as the declared parameters. We use Gaussian and diffusion approximations to characterize the aggregate traffic stream, and use fuzzy control strategy to combine model and measurement results to derive simple closed-form formulas to estimate the equivalent bandwidth in real time. We validate the proposed algorithms for various variable bit-rate traffic profiles and show that the system utilization can be substantially improved by appropriately tuning the fuzzy logic controller to combine traffic characteristics deduced from the declared parameters and traffic measurements     

Call admission control scheme with normalized quality of service metric in IEEE 802.16 networks

IEEE 802.16 network introduces a multimedia data scheduling service with different quality of service (QoS) requirements. The scheduling service manages transmission resources according to data types, satisfying the requirements of different connections or users. On the basis of the data types defined in the service, we discuss a normalized QoS metric for the multimedia connections in the paper. The QoS value of a connection can be determined just by three components: the data type of the connection, its desired resources, and its allocated resources. Then, we propose an optimum bandwidth allocation solution, which can maximize the utility of base station. Next, we propose a call admission control scheme utilizing the bandwidth allocation solution. In the scheme, the occupied resource of ongoing connections will be regulated for the entry admission of a new connection, without degrading the network performance and the QoS of ongoing connections. Finally, the simulation results confirm that the proposed scheme with the normalized QoS can achieve better trade‐off between ongoing connections and new connections.Copyright © 2012 John Wiley & Sons, Ltd.     

Dynamic resource allocation in ATM networks

This article investigates resource allocation in ATM networks and emphasizes bandwidth allocation. Resource allocation methods are categorized, and static and dynamic allocation strategies are compared. Dynamic allocation uses actual traffic behavior, while static allocation uses only the reference traffic condition given a priori. Examples of dynamic allocation strategies are available bit rate flow control, dynamic connection admission control, and dynamic VP bandwidth control. Dynamic resource allocation is shown to be promising for situations where the a priori reference model is unclear     

ATM modelling: parameterisation of 4-phase MMPP model for admissioncontrol of superposed traffic sources

A new approach is adopted to parameterise the 4-phase Markov modulated Poisson process (MMPP) to find the 4-phase arrival and transition rate parameters. This parameterisation is a major step in applying the 4-phase MMPP model to asynchronous transfer mode (ATM) modelling in the connection admission control (CAC) and in the bandwidth allocation of traffic