Impact on vertical handoff decision algorithm by the network call admission control policy in heterogeneous wireless networks
- Authors: Sharna, Shusmita , Murshed, Manzur
- Date: 2012
- Type: Text , Conference proceedings
- Relation: 2012 IEEE 23rd International Symposium on Personal, Indoor and Mobile Radio Communications, Sydney, Sept. 9th-12th 2012, pp.893-898
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- Description: Vertical handoff plays an important role to provide seamless connectivity for a mobile user in an overlapped multinetwork environment. On the other hand in order to maintain network stability, efficient management of available radio resource becomes crucial as network operators want high network utilization and maximum profit generation. For vertical handoff management, existing research works considered these user centric vertical handoff decision algorithm and network centric call admission control as two isolated decision mechanisms in heterogeneous wireless environment. In this paper, however, we propose a correlation between vertical handoff decisions and call admission control policies. We have developed a novel vertical handoff decision model using the Markov decision process based vertical handoff decision algorithm by refining the optimality criterion to factor in the probabilistic consequence of the call dropping rates so that mobile-centric vertical handoff decision algorithm and network-centric call admission control can work through a feedback mechanism to maximize respective objectives in synergy.
Adaptive weight factor estimation from user preferences for vertical handoff decision algorithms
- Authors: Sharna, Shusmita , Murshed, Manzur
- Date: 2011
- Type: Text , Conference paper
- Relation: IEEE Wireless Communications and Networking Conference (WCNC) (Mony de Swaan Adali 28 March 2011 to 31 March 2011) p. 1143-1148
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- Description: Estimating weight factors for QoS parameters plays an important role in the effectiveness of vertical handoff decision algorithms. This paper presents a novel weight estimation technique, which can adaptively control the spanning of the weights in response to user preference. Simulation results show the supremacy of the technique against the state-of-the-art in achieving wider spanning of the expected values of all QoS parameters under consideration.
An enhanced-MDP based vertical handoff algorithm for QoS support over heterogeneous wireless networks
- Authors: Sharna, Shusmita , Amin, Mohammad , Murshed, Manzur
- Date: 2011
- Type: Text , Conference proceedings
- Relation: Proceedings of 2011 IEEE International Symposium on Network Computing and Applications (NCA 2011),Cambridge, MA, 25-27th Aug, 2011
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- Description: Vertical handoff plays an important role in guaranteeing users to be always connected in an overlapped multi-network environment. During the vertical handoff procedure, handoff decision is the most important step that affects the normal working of communication. An incorrect handoff decision or selection of a non-optimal network may result in undesirable effects such as higher costs, poor quality of service (QoS) experience, and even dropped communication. Among the existing vertical handoff decision algorithms, the Markov Decision Process (MDP) based algorithm by Stevens-Navarro et al. is promising due to its ability to achieve the optimal expected reward. However, the reward function used by this algorithm is flawed as it favors reducing expected number of vertical handoffs at the expense of diminished expected values of other QoS parameters. This paper presents an extended MDP based algorithm (EMDP) with novel reward function formulation. Analysis shows that EMDP outperforms the MDP based algorithm in terms of improved expected values of all QoS parameters considered while keeping the vertical handoff number reasonably low.
Call admission control policy for multiclass traffic in heterogeneous wireless networks
- Authors: Sharna, Shusmita , Amin, Mohammad , Murshed, Manzur
- Date: 2011
- Type: Text , Conference paper
- Relation: International Symposium on Communications and Information Technologies (ISCIT) p. 433-438
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- Description: An increasing demand for wireless access to packetbased services has, in turn, driven the need for call admission control strategies to make network roaming more seamless. This paper investigates the optimal call admission control (CAC) policy for heterogeneous wireless networks based on Markov Decision Process (MDP) and Value Iteration Algorithm (VIA). We concentrate on the optimization problems of when different type of calls (i.e., new calls, vertical handoff calls, and horizontal handoff calls) can be admitted into the system where each call may have single or multiple channel requirements (multiclass). Experimental results confirm that the proposed technique can effectively control call admission of a highly dynamic heterogeneous system, which will be crucial for accommodating vertical handoff decision algorithms
Performance improvement of vertical handoff algorithms for QoS support over heterogenuous wireless networks
- Authors: Sharna, Shusmita , Murshed, Manzur
- Date: 2011
- Type: Text , Conference proceedings
- Relation: Proceedings of the Thirty-Fourth Australasian Computer Science (ASSC 2011), 17th -20th January, Perth, 2011 p. 17-24
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- Description: During the vertical handoff procedure, handoff decision is the most important step that affects the normal working of communication. An incorrect handoff decision or selection of a non-optimal network can result in undesirable effects such as higher costs, poor service experience, degrade the quality of service and even break off current communication. The objective of this paper is to determine the conditions under which vertical handoff should be performed in heterogeneous wireless networks. In this paper, we present a comprehensive analysis of different vertical handoff decision algorithms. To evaluate tradeoffs between their performance and efficiency, we propose two improved vertical handoff decision algorithm based on Markov Decision Process which are referred to as MDP_SAW and MDP_TOPSIS. The proposed mechanism assists the terminal in selecting the top candidate network and offer better available bandwidth so that user satisfaction is effectively maximized. In addition, our proposed method avoids unbeneficial handoffs in the wireless overlay networks.
Performance analysis of vertical handoff algorithms with QoS parameter differentiation
- Authors: Sharna, Shusmita , Murshed, Manzur
- Date: 2010
- Type: Text , Conference paper
- Relation: 12th IEEE International Conference on High Performance Computing and Communications p. 623-628
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- Description: Despite recent interests in developing vertical handoff decision algorithms, an essential component of the architecture of the next generation heterogeneous wireless networks, very few studies have so far reported any meaningful comparative performance analysis. This paper attempts to fill this gap in the literature by presenting a comprehensive study on the performance of three vertical handoff decision algorithms, namely, SAW (Simple Additive Weighting), TOPSIS (Technique for Order Preference by Similarity to Ideal Solution), and MDP (Markov Decision Process). We have used both analytical and simulation tools (ns-2.29) to evaluate and compare expected total QoS offerings in the mean duration of a service under different state transition probability distributions, user perception models on the importance of QoS parameters, and network switching costs. To our surprise, we have observed TOPSIS achieving the best performance despite MDP's using the optimal policy. We suspect that the user satisfiability model used in MDP to estimate link rewards might have contradicted the underlying user perception model used to estimate normalised weight of each QoS parameter, which will be investigated in future.