Multimedia Cellular Networks Research Articles

Location and Direction Estimation-Based Resource Reservation Scheme for the Handoff in Micro Cellular Multimedia Networks

This paper proposes resource reservation scheme for the handoff control to accommodate mobile multimedia traffic using the location estimation and the direction estimation. This proposed scheme uses a novel mobile tracking method based on fuzzy multi-criteria decision making, in which uncertain parameters such as pilot signal strength, distance between the mobile terminal and the base station, the moving direction, and the previous location are used in the decision process using the aggregation function in fuzzy set theory. With the position information, the moving direction is determined. The handoff requests for real time sessions are handled based on the direction prediction and the resource reservation scheme. The radio resources in the estimated adjacent cells should be reserved and allocated to guarantee the continuity of the real-time sessions. In performance analysis, our proposed scheme provides a better performance than the previous schemes.

Optimization of Fuzzy Cluster Nodes in Cellular Multimedia Networks

Optimization of Fuzzy Cluster Nodes in Cellular Multimedia Networks

Robustness of optimal channel reservation using handover prediction in multiservice wireless networks

The aim of our study is to obtain theoretical limits for the gain that can be expected when using handover prediction and to determine the sensitivity of the system performance against different parameters. We apply an average-reward reinforcement learning approach based on afterstates to the design of optimal admission control policies in mobile multimedia cellular networks where predictive information related to the occurrence of future handovers is available. We consider a type of predictor that labels active mobile terminals in the cell neighborhood a fixed amount of time before handovers are predicted to occur, which we call the anticipation time. The admission controller exploits this information to reserve resources efficiently. We show that there exists an optimum value for the anticipation time at which the highest performance gain is obtained. Although the optimum anticipation time depends on system parameters, we find that its value changes very little when the system parameters vary within a reasonable range. We also find that, in terms of system performance, deploying prediction is always advantageous when compared to a system without prediction, even when the system parameters are estimated with poor precision.

Cellular network bandwidth management scheme by using Nash bargaining solution

Bandwidth is an extremely valuable and scarce resource in wireless networks. Therefore efficient bandwidth management plays an important role in determining network performance. Adaptive bandwidth reservation and borrowing algorithms are proposed for multimedia cellular networks here. Based on the well known game-theoretic concept of bargaining, wireless bandwidth is controlled as efficiently as possible while ensuring quality-of-service (QoS) guarantees for higher-priority traffic services. Under dynamic network condition changes, control decisions in the proposed algorithms are made adaptively to strike a well-balanced network performance. This dynamic online approach can provide adaptability, feasibility and efficiency for real-world network operations. With a simulation study, the proposed scheme approximates an optimised solution under widely diverse traffic load intensities.

Dynamic Handoff Priority Adjustment Based on Mobility-Awareness in Multimedia Cellular Networks

In multimedia cellular networks, when a Mobile Host requests multimedia services, it may experience hand-offs to several cells before the request is completely served. If a target cell cannot provide adequate bandwidth for a service request, instead of directly dropping the request, the MH is put into the handoff queue and hopefully the requested bandwidth can be satisfied by later released bandwidth. Obviously, it is important to properly assign priorities for queued handoff of MHs based on their inborn dynamics to avoid unnecessary dropping. In this paper, we present a dynamic handoff priority adjustment scheme which applied a handoff queuing scheme to dynamically adjust handoff priority based on receiving signal strength, service class, and mobility of Mobile Hosts. In addition, idle bandwidth reserved by inactive MHs is reallocated to urgent handoff MHs to reduce the call dropping probability. The goal of the proposed dynamic handoff priority adjustment scheme is to further reduce call dropping probability while still maintaining high bandwidth utilization and acceptable call blocking probability on multimedia cellular networks.

Optimal admission control in multimedia mobile networks with handover prediction

Admission control is one of the key traffic management mechanisms that must be deployed in order to meet the strict requirements for dependability imposed on the services provided by modern wireless networks. We study the problem of optimizing admission control policies in mobile multimedia cellular networks when predictive information regarding the movement of mobile terminals is available. For the optimization process we deploy a novel reinforcement learning approach based on the concept of after states. The results obtained define theoretical limits for the gain that can be expected when using handover prediction, which cannot be established by deploying heuristic approaches. Numerical results show that the performance gain is a function of the anticipation time with which the admission controller knows the occurrence of handovers, and an optimal anticipation time exists. We also compare an optimal policy obtained deploying our approach with a previously proposed heuristic prediction scheme, showing that there is still room for technological innovation.

A Reinforcement Learning Approach for Admission Control in Mobile Multimedia Networks with Predictive Information

We study the problem of optimizing admission control policies in mobile multimedia cellular networks when predictive information regarding movement is available and we evaluate the gains that can be achieved by making such predictive information available to the admission controller. We consider a general class of prediction agents which forecast the number of future handovers and we evaluate the impact on performance of aspects like: whether the prediction refers to incoming and/or outgoing handovers, inaccurate predictions, the anticipation of the prediction and the way that predictions referred to different service classes are aggregated. For the optimization process we propose a novel Reinforcement Learning approach based on the concept of afterstates. The proposed approach, when compared with conventional Reinforcement Learning, yields better solutions and with higher precision. Besides it tackles more efficiently the curse of dimensionality inherent to multimedia scenarios. Numerical results show that the performance gains measured are higher when more specific information is provided about the handover time instants, i.e. when the anticipation time is deterministic instead of stochastic. It is also shown that the utilization of the network is maintained at very high values, even when the highest improvements are observed. We also compare an optimal policy obtained deploying our approach with a previously proposed heuristic prediction scheme, showing that plenty of room for technological innovation exists.

Combined fair packet scheduling policy and multi‐class adaptive CAC scheme for QoS provisioning in multimedia cellular networks

AbstractIn this paper, we propose a combined multi‐class adaptive connection admission control algorithm and a new fair packet scheduling policy, based on an enhanced weighted fair queuing algorithm. It takes into account a realistic behaviour of traffic while considering the spatial variation of the system characterizing both the user mobility and the signal propagation impairments due to the surrounding effects. The proposed allocation scheme provides enhanced traffic performance in heterogeneous environments and achieves a good level of capacity gain. The new adaptive quality of service (QoS) oriented connection admission control (CAC) function is proposed to meet the rapidly increasing demand for providing multimedia services with diversified quality requirements. It decides whether the connection request is to be admitted into the system, on the basis of the generated interference level and the waiting time before access. This CAC scheme, based on service class differentiation, aims at maximizing the use of available radio resource and meeting the QoS requirement of higher priority users as much as possible while maintaining the minimum requirements of lower priority users, especially when the system suffers from congestion. The results indicate that significantly increased traffic performance can be achieved in comparison with other conventional investigated policies. Copyright © 2006 John Wiley & Sons, Ltd.

Quality of Service Management Scheme for Adaptive Service in Wireless/Mobile Multimedia Cellular Networks

An adaptive service framework is expected to support real-time multimedia services in wirless/mobile cellular networks with various classes of traffic and diverse bandwidth requirements. Quality of service (QoS) provisioning in an adaptive framework is another challenging consideration, such as quantifying the level of bandwidth degradation of an ongoing calls and guaranteeing stable QoS levels. Considering both the period and the depth of degradation, the degradation area ratio (DAR) represents the average ratio of a call's degradation and is one of the meaningful measures for adaptive service in call level analysis. In this paper, analytical models for estimating the DAR and finding the optimal control parameters are presented in multi-class traffic call management situations. In complete partitioning capacity based threshold-type call admission control (CAC). a one-dimensional Markov chain with an absorbing state is proposed for estimating the DAR in each traffic class. We formulate a two-leveled optimization problem minimizing the total blocking probabilities subject to QoS requirements and present the procedures required in finding the optimal capacities and threshold values by using modified dynamic programming. In complete sharing capacity based threshold-type CAC, the multidimensional Markov model is approximately reduced to a one-dimensional model in order to reduce complexity and hence calculation time. The reduced model is compared with multidimensional Markov model in numerical examples. The optimization problem is formulated minimizing the total blocking probabilities subject to QoS requirements and the optimal threshold parameters are found by using a genetic algorithm. Performance of two adopted admission policies in adaptive framework situations is illustrated by numerical results.

An adaptive min–max fair bandwidth allocation scheme for cellular multimedia networks

AbstractDepending on the flexibility in controlling the transmission rate and the differences between on‐line (real time) and off‐line transmission modes, multimedia applications can potentially include a wide range of services, with the traditional stringent quality‐of‐service (QoS) requirement at the extreme to the highly adaptive ones that can tolerate or smartly adapt to the transient fluctuations in the QoS parameters. Keeping the cellular multimedia networks efficient with low call dropping and blocking rates and high bandwidth utilisation while maintaining a fair distribution of bandwidth by synergistically addressing the differences among these services remains a significant challenge. This paper addresses this issue by developing a novel min–max fairness scheme where bandwidth is distributed with equal share only after ensuring the minimum requirements. Besides borrowing in‐use bandwidth through redistribution, this scheme also allows for using the reserved bandwidth for the offline services. Simulation results confirm the superiority of this scheme against the rate‐based borrowing and the max–min fairness schemes, the two most recent works addressing similar issues. Copyright © 2005 AEIT.

Adaptive fault tolerant bandwidth management framework for multimedia cellular networks

The design of reliable and fault-tolerant bandwidth management algorithms for mobile cellular networks is an important issue. It has not received much attention in the literature. In the paper, an adaptive fault tolerant scheme that provides high quality of service (QoS) to users in a multimedia cellular network is developed. The most important feature of the algorithm is its ability to respond to current network traffic conditions based on real time estimates. It does not reduce network capacity during normal conditions and adapts to the loss of one or more base stations via the fault tolerance mechanism. With a simulation study, the excellent performance of the scheme for diverse scenarios including failure modes is demonstrated.

An Integrated Adaptive Bandwidth-Management Framework for QoS-Sensitive Multimedia Cellular Networks

Bandwidth is an extremely valuable and scarce resource in a wireless network. Therefore, efficient bandwidth management is necessary in order to provide high-quality service to users in a multimedia wireless/mobile network. In this paper, we propose new online bandwidth-management algorithms for bandwidth reservation, call admission, bandwidth migration, and call-preemption strategies. These techniques are combined in an integrated framework that is able to balance the traffic load among cells accommodating heterogeneous multimedia services while ensuring efficient bandwidth utilization. In addition, our online framework to adaptively control bandwidth is a cell-oriented approach that has low complexity, which makes it practical for real cellular networks. Simulation results indicate the superior performance of our bandwidth-management framework to strike the appropriate performance balance between contradictory quality-of-service requirements.

An Enhanced Handoff Control Scheme for Multimedia Traffic in Cellular Networks

This letter presents an enhanced handoff control scheme allowing dynamic bandwidth sharing between different types of traffic for improving bandwidth utilization in multimedia mobile cellular networks. Performance results for the proposed scheme are obtained analytically and by simulation. The results demonstrate superior efficiency achieved by the proposed scheme.

Priority-Determined Multiclass Handoff Scheme With Guaranteed Mobile QoS in Wireless Multimedia Networks

The provision of multiclass services is gaining wide acceptance and will be more ubiquitous in future wireless and mobile systems. The crucial issue is to provide the guaranteed mobile quality of service (QoS) for arriving multiclass calls. In multimedia cellular networks, we should not only minimize the dropping rate of handoff calls, but also control the blocking rate of new calls at an acceptable level. This paper proposes a novel multiclass call-admission-control mechanism that is based on a dynamic reservation pool for handoff requests. In this paper, we propose the concept of servicing multiclass connections based on priority determination through the combined analysis of mobile movement information and the desired QoS requirements of multimedia traffic. A practical framework is provided to determine the occurrence time of handoff-request reservations. In our simulation experiments, three kinds of timers are introduced for controlling the progress of discrete events. Our simulation results show that the individual QoS criteria of multiclass traffic such as the handoff call-dropping probability can be achieved within a targeted objective and the new-call-blocking probability is constrained to be below a given level. The proposed scheme is applicable to channel allocation of multiclass calls over high-speed wireless multimedia networks.

Dynamic bandwidth sharing for handoff traffic in multimedia mobile cellular networks

An efficient handoff control scheme using dynamic bandwidth sharing in multimedia mobile cellular networks is presented. The numerical results show that compared to the commonly used bandwidth reservation based handoff control scheme, higher bandwidth utilisation is achieved in the proposed scheme under different traffic loading distributions, while lower call dropping probabilities are also maintained.