Quality of Experience Based Cross-Layer Design of Mobile Video Systems
Mobile communication systems provide powerful means of expanding the environment with which humans can interact. This is accompanied by a shift from human-to-human communication (voice) to human-to-human interaction (multimedia) with the communication partners expecting always best Quality of Experience (QoE). As humans are the final judges of service quality, a key issue largely neglected in research becomes the creation of experiences that closely resemble human-to-human interaction.
Recently, the importance of taking care of user satisfaction with service provisioning as a whole has been realized. The related QoE concept covers end-to-end (E2E) Quality of Service (QoS) parameters, factors such as coverage or support, and subjective factors such as expectations of and experiences with the service. Clearly, satisfactory service delivery demands technologies that support intuitive and scalable human interaction addressing issues such as mobility, functionality, and maintainability of the service including status information towards providers and customers. To monitor and adapt QoE, performance indicators that represent service integrity, e.g. throughput, delay, jitter, data loss, bit error rate (BER), peak signal-to-noise ratio (PSNR) and many others, have to be selected and related to objective measures that correlate well with the quality as perceived by humans and thus can be used to optimize quality perception in technical systems. On the other hand, the rapid evolution of mobile networks is driven by the growth of packet data applications such as mobile multimedia and video applications, and mobile streaming services. Also, heterogeneous network structures, severe channel impairments, and complex traffic patterns make mobile scenarios much more unpredictable as their wired counterparts. A major challenge is hence the design of mobile networks and services that fulfil the stringent QoE requirements of the many emerging mobile video applications. In contrast to traditional layer-independent protocol stack designs, this projects aims at a much more flexible, QoE-based cross-layer design paradigm as this will be critical in the development of technologies suitable for mobile video systems.
The benefits of our approach over traditional concepts reaches from computationally efficient video processing techniques over reduced power consumption of mobile terminals to real-time scheduling, resource and network management techniques. This in turn enables the user to be longer connected, and to expand even further up in the value chain by increasing available system capacity allowing operators to accommodate more users into the same coverage area. To meet these objectives and challenges in the context of such a difficult medium as the radio channel, it is required to identify and develop novel cross-layer protocol architectures, stacks, monitoring and control facilities along with a theoretical framework, methods, and algorithms for exploiting these measures for mobile communication and service management. The project involves a showcase connected to the application portfolio of our industrial partners in which a mobile video service will be provided to users in a live system. The key activities of the proposed project are as follows:
Application: This project part is concerned with QoE monitoring and performance assessment from the end users and mobile video applications point of view. This includes identification of the relevant video artifacts along with the related video features. As such, mobile video processing will play an important role in this area.
Middleware: This project part aims to provide a multithreaded software architecture that can benefit from the multi-core processors chips that are currently making their way into handheld devices. The software architecture must also be adaptable so that the application software can adapt to changing environments, e.g. different bandwidth and different hardware resources in the terminals (including multi-core processors).
Networking: This project part is concerned with monitoring and on-line analysis of the packet delivery process at the mobile network interface of the handheld and at the network interface of the server. Such monitoring is motivated by the fact that disturbances on network level affect the E2E-QoS and thus the QoE.
Cross-layer management: This project part serves as an overlay to the application, middleware, and networking components and develops the cross-layer mechanisms and management strategies among these functionalities. Accordingly, this project area has to deal with the relationship between resource management and QoE constraints more fundamentally to reveal potential cross-layer strategies and to select those that can be tested in the showcase.
Showcase: The showcase is going to be selected from the application portfolio of our partner WIP, which offers the project access to application areas including mobile health, stock trading, and mobile streaming services for the Karlskrona naval museum. The showcase and related field tests will be used to verify favorable cross-layer design approaches in a live system.
The research group at BTH reflects the interdisciplinary nature of the project as it links research fields of three departments. These are the Networking Group at the Department of Telecommunication Systems, the Radio Communications Group at the Department of Signal Processing, and the Computer Systems Engineering Group at the Department of Systems and Software Engineering.
Dr.-Ing. Markus Fiedler
Prof. Dr.-Ing. Hans-Jürgen Zepernick
Prof. Dr. Lars Lundberg
Dr. Mats Pettersson
Dr. Patrik Arlos
Mr. Hussein Aziz
Mr. Tahir Nawaz Minhas
Mr. Duong Quang Trung
Mr. Feng Wang