Despite decades of evolution, the fundamental trust model of mobile networks remains unchanged. As a result, each mobile device has its own identity chip with network access credentials to be able to use mobile services such as voice telephony or Internet access. The upcoming Internet of Everything (IoE) revolution leads to a massive increase in connected devices and challenges the scalability of this approach. We propose to simplify trust establishment and show how the identity chips storing the credentials can be eliminated for most devices. The key idea is a new trust model in which an authorized subscriber securely delegates trust to other devices such that these other devices can claim legitimacy to connect to the mobile network. Our analysis shows that this proposal significantly reduces costs compared to the 5G trust model.

Through successive technological innovation, mobile networks have been able to cope with traffic growth and the changing nature of services. However, there is still a gap between the possible transformation in terms of performance and efficiency, and the emerging new service requirements. This paper presents the ongoing mobile network evolution towards 5G, with a focus on the emerging network slicing concept, supposed to cope with the disparate requirements of future services and applications. Network slicing allows for the coexistence of different architectures to address disparate service requirements in a more efficient way. A slice selection function is a key element in the future core network architecture, enabling the UE to be allocated to a proper slice. We proposed a new slice selection mechanism allowing the UE to connect to multiple slices based on service type. The standardization status on this matter and the technical aspects of the proposed selection function are discussed.

Providing smooth Handover (HO) for video applications over wireless networks is often difficult due to the different amount of available resources from cell to cell. In this paper, we propose a QoE-based scheme that statically or dynamically reserves resources in order to maintain unperceivable quality fluctuation during HO for video delivery in LTE mobile networks. Through simulations, we show that reallocating the wireless resource in a cross-layer fashion is not enough to maintain the video quality within unperceivable range. Reserving fixed amount of resources solves the problem, however, it leads to inefficient resource utilization and overall service quality degradation. To reduce unnecessary resource reservation, we propose reserving the actual resource demand dynamically upon a prior knowledge of HOs. A comparison between our proposed schemes and a conventional QoE-based scheme is done by performing simulations using an OPNET LTE simulator. Results show that our proposed schemes lead to significant improvements of HO user-perceived quality.

This paper proposes a novel approach for Quality of Experience (QoE) driven cross-layer optimization for wireless video transmission. We formulate the cross-layer optimization problem with a constraint on the temporal fluctuation of the video quality. Our objective is to minimize the temporal change of the video quality as perceivable quality fluctuations negatively affect the overall quality of experience. The proposed QoE scheme jointly optimizes the application layer and the lower layers of a wireless protocol stack. It allocates network resources and performs rate adaptation such that the fluctuations lie within the range of unperceivable changes. We determine corresponding perception thresholds via extensive subjective tests and evaluate the proposed scheme using an OPNET High Speed Downlink Packet Access (HSDPA) emulator. Our simulation results show that the proposed approach leads to a noticeable improvement of overall user satisfaction for the provided video delivery service when compared to state-of-the-art approaches.

The increasing popularity of user-generated content and the high quality upstreaming capabilities of mobile phones indicate a prevalence of video traffic in the uplink of next generation mobile net works. Need arises for optimizing the network resource allocation while preserving the user satisfaction. In this paper, we propose a service-centric approach for uplink distribution of real-time user generated content based on the Quality of Experience (QoE) and popularity of the video content. In case of limited network resources, the proposed approach assigns more resources for popular contents while maintaining a minimum guaranteed QoE for the less popular ones. We compare our service-centric approach with a QoE-driven one that does not consider video popularity and evaluate both approaches for the uplink of an LTE system. The simulation results show that a significant gain in terms of average user satisfaction can be achieved.

This paper proposes a Quality of Experience (QoE) based rate adaptation scheme selection approach for multi-user wireless video delivery. Transcoding and packet dropping are used as examples of rate adaptation schemes, and we investigate their impact on user perceived video quality. In the presence of constrained computation resources, the most suitable rate adaptation scheme is determined for each video stream such that the overall quality degradation is minimized. The proposed scheme selection approach is integrated with QoE-based resource allocation in presence of constrained transmission resources. Simulation results obtained from an emulated High Speed Downlink Packet Access (HSDPA) show that the QoE-based approach leads to significant improvements of user perceived quality compared to other approaches including a non-optimized HSDPA systems

Thanks to its in-network drop-based adaptation capabilities, H.264 Scalable Video Coding is perceived as an effective approach for delivering video over networks characterized by sudden large bandwidth fluctuations, such as Wireless LANs. Performance may be boosted by the adoption of application-aware/cross-layer schedulers devised to intelligently drop video data units (NALUs), so that i) decoding dependencies are preserved, and ii) the quality perceived by the end users is maximized. In this paper, we provide a theoretical formulation of a QoE utility-optimal cross-layer scheduling problem for H.264 SVC downlink delivery over WLANs. We show that, because of the unique characteristics of the WLAN MAC operation, this problem significantly differs from related approaches proposed for scheduled wireless technologies, especially when the WLAN carries background traffic in the uplink direction. From these theoretical insights, we derive, design, implement and experimentally assess a simple practical scheduling algorithm, whose performance is very close to the optimal solution.

This paper describes the H.264 scalable video coding streaming evaluation framework (SVEF). This is the first open-source framework for experimental assessment of H.264 scalable video coding (SVC) delivery over real networks. Effectively adapting of the transport of an H.264 SVC stream to time-varying, bandwidth constrained, and loss prone networks is an important research area. However, very little experimental work has been performed due to the unavailability of real-time H.264 SVC players, the limitations of existing decoding software libraries when challenged with network-imparied received SVC streams (e.g., affected by random loss of Network Abstraction Layer Units - NALUs), and the lack of solutions for SVC streaming support. SVEF overcomes these issues by developing missing components and by integrating them in a hybrid online/offline experimental framework. We believe SVEF will be of significant help to the research community interested in experimentally benchmarking their own proposed SVC adaptation approaches and delivery mechanisms. As a proof-of-concept of SVEF, we provide the experimental performance evaluation of an SVC cross-layer in-network scheduler in a wireless LAN hot spot scenario.

We address the problem of rate allocation and network/path selection for multiple users, running simultaneous applications over multiple parallel access networks. Our joint optimization problem consists of finding the appropriate application rate allocation and network parameters for each individual user, such that an overall quality metric is maximized. We compare our solution to other solutions based on throughput optimization strategies through extensive simulations, and we show the superiority of our approach. Furthermore, our solution proves to be more robust in dynamic systems, when clients can join/leave the access networks.

Presence has taken shape as a way to present a comprehensive view of the communications capabilities of a user or resource. Standardized protocols allow for receiving presence data from a variety of sources, such as a user's communication devices, cellular provider, online calendar and sensors in his environment. This data can describe many different aspects of his communication capability, such as his device characteristics, activities, and even physical locations. The large number of presence sources may lead to irrelevant or inconsistent data. Also, the data may be incomplete and not as usable as it could be to the presence watcher. This paper proposes the use of presence composition to remove unusable data and create new more usable data. We discuss the details of this composition and present a format with which a user can specify a policy for composition.

Abstract — We address the problem of video streaming over multiple parallel networks. In the context of multiple users, accessing different types of applications, we are looking for efficient ways of allocating network resources and selecting network paths for each application, in order to maximize the overall systems performance. Our optimization joint problem consists of finding the appropriate application rate allocation and network parameters for each individual user, such that a universal system quality metric is maximized. A specific mapping between the requirements of each considered application and the overall quality metric is introduced, and our results are compared to other solutions based on throughput optimization strategies. The superiority and robustness of our approach is shown through extensive simulations in constant and dynamic systems, when clients can join/leave the access networks. Furthermore, we introduce heuristic algorithms which can obtain good results and are inexpensive in terms of computation and execution time. I.

Service usage in emerging ubiquitous environments includes seamless and personalized usage of public and private devices discovered in the vicinity of a user. In our work, we describe an architecture for device discovery, device configuration, and the transfer of active sessions between devices. The presented architecture uses the Session Initiation Protocol (SIP) as a standardized, widely used signaling protocol for IP-based multimedia services. Our solution includes support of simple existing devices, split of sessions between devices, user-control of location-based behavior, and handling of security and privacy concerns. We present the implementation and show the feasibility of our work with analytical evaluation and measurements.

With the convergence of the Internet and the mobile communications world, Internet-based services may become available on any user device. In order to make efficient use of such a ubiquitous environment the user demands to access his personalized services from any place, anytime and on any device regardless of the type of access network. In particular, we consider the situation that a user transfers a running session between devices. We refer to this as session mobility. Providing such ubiquitous services transparently to the user, is not only challenging from a networking point of view but also poses severe requirements on the management operations and in particular accounting needed for a commercial service rollout. We describe an accounting architecture for session mobility. It allows the network operators to determine, collect and evaluate data on service usage when users transfer their ongoing communication session(s) from one device to another or a set of devices within its domain or across multiple operators' environments. In particular, we describe the interactions required between the signaling protocol and the accounting protocol in support of session mobility.

We present a location-based, ubiquitous service architecture, based on the session initiation protocol (SIP) and a service discovery protocol that enables users to enhance the multimedia communications services available on their mobile devices by discovering other local devices, and including them in their active sessions, creating a "virtual device." We have implemented our concept based on Columbia University's multimedia environment and we show its feasibility by a performance analysis.