Jyrki Huusko

Cross-layer architecture for scalable video transmission in wireless network

Multimedia applications such as video conference, digital video broadcasting (DVB), and streaming video and audio have been gaining popularity during last years and the trend has been to allocate these services more and more also on mobile users. The demand of quality of service (QoS) for multimedia raises huge challenges on the network design, not only concerning the physical bandwidth but also the protocol design and services. One of the goals for system design is to provide efficient solutions for adaptive multimedia transmission over different access networks in all-IP environment. The joint source and channel coding (JSCC/D) approach has already given promising results in optimizing multimedia transmission. However, in practice, arranging the required control mechanism and delivering the required side information through network and protocol stack have caused problems and quite often the impact of network has been neglected in studies. In this paper we propose efficient cross-layer communication methods and protocol architecture in order to transmit the control information and to optimize the multimedia transmission over wireless and wired IP networks. We also apply this architecture to the more specific case of streaming of scalable video streams. Scalable video coding has been an active research topic recently and it offers simple and flexible solutions for video transmission over heterogeneous networks to heterogeneous terminals. In addition it provides easy adaptation to varying transmission conditions. In this paper we illustrate how scalable video transmission can be improved with efficient use of the proposed cross-layer design, adaptation mechanisms and control information.

Towards a New Architectural Framework – The Nth Stratum Concept

Current architectures and solutions are about to reach the limits of sustainable developments. Over the years, many new requirements have emerged, and there are observations pointing to an ever-increasing diversity in applications, services, devices, types of networks at the edge and the access. Meanwhile, the infrastructures for internetworking, connectivity, and also management remain fairly the same. A new paradigm is needed that can support a continuous high pace of innovations in all the different parts and aspects of a communication system, while at the same time keeping costs of deployment and maintenance down. This new paradigm has to embrace current trends towards increased heterogeneity, but on the other hands provide support for co-existence and interoperability between alternative and various solutions all residing within a global communication system. This paper presents a new architectural framework called the Nth Stratum concept, and which takes a holistic approach to tackle these new needs and requirements on a future communication system.

MAC layer QoS architecture for optimized and fair transmission of scalable video

The increasing demand for mobile video delivery has boosted the development of mechanisms which improve the Quality of Service (QoS) of video transmission through bitstream adaptation. In this paper, we study adapting H.264/SVC streams in the MAC layer. We introduce a generic QoS architecture for implementing both inter- and intra-traffic class QoS for scalable video streams, and verify the solution with OPNET simulations in the context of IEEE 802.11e EDCA. The results show that our two-tier hierarchical scheduling approach provides for optimized SVC delivery in. 11e networks without hampering the channel access of the other traffic types.

WiMAX backhaul for environmental monitoring

In environmental monitoring, wirelessly connected sensors form local networks and collect data, which are sent to a central repository for further analysis and permanent storage. In this paper we empirically evaluate the use of fixed WiMAX to backhaul data from an environmental monitoring application. We find that aggregating sensor readings is crucial for taking full advantage of the WiMAX backhaul. We consider application-layer aggregation for scenarios where sensor communication is programmable or at least configurable. For scenarios where sensors cannot be modified, we consider network-layer aggregation using a performance enhancing proxy. Finally, we consider the case where application- and network-layer aggregation are combined. Our results show that without aggregation, goodput is only a small fraction of the maximum achieved in our testbed. Furthermore, we examine the effect of different modulation schemes on performance and quantify in practice the number of wireless sensor nodes that could be served with different modulation and data aggregation combinations.

Analyzing transport and MAC layer in system-level performance simulation

The modern mobile embedded devices support complex distributed applications via heterogeneous multi-core platforms. For the successful deployment of these applications, the scalability and performance analysis must be performed at all the layers of OSI model. This helps to identify the potential bottlenecks at different layers to perform the necessary optimizations. To achieve this goal, a framework is needed which accurately models the functionalities at different layers. The technical contributions described in this article include the extensions of ABstract inStruction wOrkLoad & execUtion plaTform based performance simulation (ABSOLUT) for the performance and scalability analysis of Transport and Medium Access Control (MAC) layers in the system level performance simulation. The article elaborates the design accuracy of the modeled components and their application in the context of M3 (multi-device, multi-vendor, multi-domain), which is a tri-layered conceptual interoperability architecture for embedded devices. These extensions pave the way towards the full coverage of the OSI model in the system-level performance simulation of distributed embedded systems. The network simulators for example ns-2, OMNeT++ and OPNET though provide detailed models of transport and MAC protocols but do not provide any framework such that these models can be used by the application workload models to mimic the real world use-cases. Also these models do not model the execution workload of these protocols on a particular execution platform and hence cannot be used in the architectural exploration of distributed embedded systems.

BIONETS: Self Evolving Services in Opportunistic Networking Environments

This paper presents the BIONETS opportunistic service evolution platform. The proposed platform allows pervasive services to evolve over time by exploiting opportunistic communications among mobile nodes on the one hand, and evolutionary computation techniques on the other. We present the main components of the platform, describing their functionalities and technical implementation. Finally, we present the hardware–in–the–loop approach we have followed to evaluate it, where a simulation platform, in charge or reproducing a large number of mobile nodes communicating wirelessly, is integrated with a real software prototype.

Adapter Implementation between Wimax Specific Layers and Network/Application Layers

Several recent studies show that future high data rate broadband wireless access (BWA) technologies require the use of adaptive and co-operative techniques to more efficiently utilise the resources in link and system level. In this paper we propose an adapter module to be utilised in the data link layer (DLL) and optionally in the application layer to serve different adaptive triggering routines among the networks. The adapter is used to retrieve the necessary information from hardware (HW) to aid different adaptation processes in system. The adapter is also used to trigger the preferred control and management actions in the media access control (MAC) and physical (PHY) level of the related HW. The usability and performance limits of the designed and implemented adapter solutions were measured with relevant performance evaluations and the derived results validate the feasibility of the proposed adapter solution.

Trigger Management and Mobile Node Cooperation

This chapter addresses one of the challenges in cooperative networking, namely, mobility support in a heterogeneous ambient network environment. We motivate the need for efficient mechanisms for handling the large amount of network and channel state information required in assisting fast handovers and network and service adaptation strategies. Managing a variety of network and protocol events and triggering information is a challenging task even in a homogeneous networking environment when different mobility schemes (node, network, session) and application adaptation are considered and, not unexpectedly, the heterogeneity of access networks increases further the amount of such information. We present triggering management mechanisms which efficiently handle triggering information at node and network level, dealing with a greater variety of events originating from any component of the node’s protocol stack as well as mobility management entities within the network. We then discuss the benefits of arranging mobile nodes into specific mobile routing groups, and how such approaches can benefit from the availability of the triggering management mechanisms in an ambient network environment.

Performance evaluation of distributed NoTA applications on multi-core platforms

For future applications running on nomadic devices operating in smart spaces, the availability of the services and the quest for better alternative services will go hand in hand to enable the best-possible experience for the end-user. To realize it, a service-level interoperability solution must be devised that would enable applications to access services over heterogeneous platforms and various transport technologies. The recent extension of the Network-on-Terminal-Architecture (NoTA) supports service-level interoperability between mobile devices via a device interconnect protocol (NoTA DIP), enabling applications to access and discover services over multiple transport technologies in a seamless manner. A brisk performance evaluation phase is required for evaluating the feasibility of new NoTA applications on modern multi-core based mobile device platforms. To achieve this goal, NoTA Service Oriented Architecture (SOA) application components. i.e., Application Nodes (ANs) and Service Nodes (ANs) are first refined to encompassing processes and then to platform services and functions to form a layered application architecture. In next step, the NoTA SOA application model layers are mapped to ABSOLUT workload model layers employed in performance simulation. Furthermore, the ABSOLUT workload models corresponding to different NoTA DIP implementations for example NoTA DIP kernel implementation and NOTA DIP Daemon mode must be modeled and integrated to ABSOLUT. The approach is experimented with a case study. The modeled components and approach is not limited to NoTA SOA and can be used for the performance evaluation of other distributed service oriented application architectures. MARTE UML2.0 profile, Papyrus UML 2.0 modeling tool and SystemC were used for modeling and simulation.

Simulation and Implementation of the Autonomic Service Mobility Framework

The increased traffic load, proliferation of network nodes and, in particular, wireless user devices, and the boom in user services and exponential growth of information stored in content distribution networks (CDNs) have brought new challenges for current networks. One major challenge has and continues to be efficient load balancing and information access. The topics have been well studied for wired networks for, for example, process load balancing in distributed computer networks with migration. However, the wireless networks and ubiquitous computing environments create new limitations and additional requirements to perform service or process migration. In this paper, we present a simulation case and proof-of-concept implementation for service mobility as a part of the BIONETS service evolution process with the aim of optimizing service penetration in a pervasive computing environment and balancing the load in the system caused by the high service utilization rate.