A Metamodeling Approach for Cross-layer Optimization: A framework and Application to Voice over WiFi

in Simulation Modelling Practice & Theory (2011), 19(9), 2117-2129

Cross-layer design has been proposed to optimize the performance of networks by exploiting the interrelations among parameters and procedures at different levels of the protocol stack. This paper ... [more ▼]

Cross-layer design has been proposed to optimize the performance of networks by exploiting the interrelations among parameters and procedures at different levels of the protocol stack. This paper introduces a quantitative framework for the study of cross-layer interactions, which enables design engineers to analyze and quantify interlayer dependencies and to identify the optimal operating point of the system, by using network economic theory principles. The framework is then used for performance optimization of a single-cell Voice over WiFi (VoWiFi) system. Insights gained from the considered scenario enable us to define a novel cross-layer Call Admission Control (CAC) scheme. The multistage CAC takes into account Quality of Service (QoS) criteria, which provide satisfaction to the end user, as well as revenue criteria that maximize the possible profit of the WiFi provider. [less ▲]

Architectures and Cross-Layer Design for Cognitive Networks

in Handbook on Sensor Networks (2010)

Network evolution towards self-aware autonomous adaptive networking attempts to overcome the ine?ciency of con?guring and managing networks, which leads to performance degradation. In order to optimize ... [more ▼]

Network evolution towards self-aware autonomous adaptive networking attempts to overcome the ine?ciency of con?guring and managing networks, which leads to performance degradation. In order to optimize network operations, the introduction of self-awareness, self-management, and self-healing into the network was proposed. This created a new paradigm in networking, known as cognitive networking. This chapter describes state-of-the-art, as well as future directions in cognitive networking. Fundamental techniques for enabling cognitive properties, such as, adaptation, learning, and goal optimization processes are detailed in this text. A comparison of available research proposals leads to the design of a promising cognitive network architecture capable of incorporating cognitive network techniques. Finally, a discussion on the required properties of the cross-layer design for cognitive networks and deployment issues are speci?ed. [less ▲]

Introduction: Why Cross-Layer? Its Advantages and Disadvantages

in Cross Layer Designs in WLAN Systems (2010)

Packet Concatenation at the IP Level for Performance Enhancement in Wireless Local Area Networks

in Wireless Networks (2008), 14(4), 519-529

Wireless local area networks experience performance degradation in presence of small packets. The main reason for that is the large overhead added at the physical and link layers. This paper proposes a ... [more ▼]

Wireless local area networks experience performance degradation in presence of small packets. The main reason for that is the large overhead added at the physical and link layers. This paper proposes a concatenation algorithm which groups IP layer packets prior to transmission, called PAC-IP. As a result, the overhead added at the physical and the link layers is shared among the grouped packets. Along with performance improvement, PAC-IP enables packet-based fairness in medium access as well as includes QoS support module handling delay-sensitive traffic demands. The performance of the proposed algorithm is evaluated through both simulations and an experimental WLAN testbed environment covering the single-hop and the widespread infrastructure network scenarios. Obtained results underline significant performance enhancement in different operating scenarios and channel conditions. [less ▲]

Formal Methods in Cross Layer Modeling and Optimization of Wireless Networks: State of the Art and Future Directions

in Heterogeneous Next Generation Networking: Innovations and Platforms (2008)

Performance Improvement in Wireless Networks using Cross-layer ARQ

in Computer Networks (2007), 51(15), 4396-4411

This paper presents a novel cross-layer approach (LLE-TCP) designed for performance enhancement of TCP over a large variety of wireless networks. LLE-TCP avoids TCP ACK packet transmission over the ... [more ▼]

This paper presents a novel cross-layer approach (LLE-TCP) designed for performance enhancement of TCP over a large variety of wireless networks. LLE-TCP avoids TCP ACK packet transmission over the wireless channel. As a result, the saved time can be utilized by the nodes for data packet delivery. The proposed scheme enhances the protocol stacks of the wireless sender (or a base station) and the receiver with cross-layer ARQ agents which support ACK suppression. ARQ agent suppresses the outgoing ACKs at the receiver side and generates them locally at the sender or base station. The performance evaluation of the proposed approach is performed via simulations as well as IEEE 802.11 testbed experiments for single-hop and infrastructure network scenarios. LLE-TCP demonstrates the performance improvement in the range of 20–100% depending on the transmitted TCP/IP datagram size. Among the factors contributing to performance enhancement are: medium busy time reduction, reduced sensibility to link errors, reduced round trip time (RTT), and improved congestion control. A good level of throughput fairness as well as a fair coexistence with state-of-the-art TCP modifications ensures proper functionality of the proposed approach, while performance advantages extended even on non-LLE-TCP users favor an incremental deployment of the technique in existing networks. [less ▲]

Cross-Layering for Performance Improvement in Multi-Hop Wireless Networks

in Journal of Interconnection Networks (2006), 7(1), 51-61

DAWL: A Delayed-ACK Scheme for MAC-Level Performance Enhancement of Wireless LANs

in Mobile Networks and Applications (2005), 10(5), 607-615