Cross-layer protocol engineering for wireless mobile networks: part 2

his issue presents the second of the two-part feature topic series, “Cross-Layer Protocol Engineering for Wireless Mobile Networks. ” Cross-layer protocol engineering for wireless networks is an emerging research area, and addressing the relevant issues in design, analysis, and optimization of the wireless protocol stack is important for efficient operation and cost-effective deployment of next-generation wireless systems. Research on cross-layer design and engineering is interdisciplinary in nature and involves several research areas, such as signal processing, adaptive coding and modulation, channel modeling, traffic modeling, queuing theory, and network protocol design and optimization techniques. The response to our call for papers on this feature topic of IEEE Communications Magazine was overwhelming; we received a very large number of papers (over 50). All were reviewed by experts in the relevant area, and the articles selected for publication went through a rigorous two-round review process. It was decided to publish the articles in two back-to-back issues. This issue consists of seven articles covering various aspects of cross-layer analysis and design, such as cross-layer signaling architecture involving physical (PHY), medium access control (MAC), routing, and application layer functionalities, analytical methodology for cross-layer performance analysis, cross-layer design for efficient video streaming in wireless networks, and cross-layer protocol design for wireless sensor networks. The first article, “Cross-Layer Feedback Architecture for Mobile Device Protocol Stacks” by V. T. Raisinghani and S. Iyer, presents a cross-layer design architecture for enhancing the performance of existing protocol stacks in the wireless environment. This architecture is based on the idea of optimizing the cross-layer feedback signaling. A prototype implementation of this architecture is also described, and the authors demonstrate how the proposed architecture achieves the key design goals — rapid prototyping, minimum intrusion, portability, and efficiency — in a wireless LAN environment. The second article, “CrossTalk: Cross-Layer Decision Support Based on Global Knowledge” by R. Winter, J. Schiller, N. Nikaein, and C. Bonnet, presents a generic cross-layer architecture, CrossTalk, to improve the performance of the protocols at the different layers of a wireless protocol stack. This architecture is based on the concept of data dissemination and uses two data management entities; one is responsible for the organization of locally available information (i.e., local view) that is accessible to protocols at each layer, and the other establishes a network-wide or global view of the same type of information collected in the local view. The global view is used to evaluate the relative state of a node, and the decision processes at the different protocol layers use this relative state information. The authors present a reference application of the proposed architecture for load balancing through routing in wireless ad hoc networks. The third article, “Cross-Layer-Based Modeling for Quality of Service Guarantees in Mobile Wireless Networks” by X. Zhang, J. Tang, H. -H. Chen, S. Ci, and M. Guizani, presents a cross-layer model to investigate the impact of the advanced physical-layer techniques such as multiple-input multiple-output (MIMO) diversity and adaptive modulation and coding (AMC) on radio link layer performance in the wireless protocol stack. The numerical results show that AMC and MIMO diversity at the physical layer significantly impact the statistical quality of service (QoS) performance at the radio link layer. The proposed model would be useful for developing efficient admission control and radio resource management techniques for multimedia wireless networks. High-speed multimedia service is one of the key drivers for evolution of the next-generation wireless networks. The recently developed H.264-based video is expected to be an important component of many wireless multimedia services such as videoconferencing and real-time network gaming. The fourth article in this special issue, “Towards an Improvement of H.264 Video Transmission over IEEE 802.11e through a Cross-Layer Architecture” by A. Ksentini, A. Guéroui, and M. Naimi, presents a cross-layer (application, transport, and MAC) architecture for efficient transmission of H.264-coded video over IEEE 802.11e-based wireless LANs. This architecture uses efficient error resilience mechanisms at the application layer and a QoS differentiation mechanism in the MAC layer to provide the desired delay and reliability performance for H.264-coded video. By simulations the authors demonstrate that the achieved performance through cross-layer optimization is superior to that of the EDCA architecture defined in the IEEE 802.11e standard. The fifth article, “Optimized Video Streaming over 802.11 by Cross-Layer Signaling” by I. Haratcherev, J. Taal, K. Langendoen, R. Lagendijk, and H. Sips, presents a cross-layer (transport and MAC) architecture for seamless video streamGUEST EDITORIAL