Timo Koskela

Network controlled Device-to-Device (D2D) and cluster multicast concept for LTE and LTE-A networks

In this paper we introduce a reliable multicast concept for Device-to-Device (D2D) communication integrated into cellular network. In addition to the introduction of the basic concept, initial simulation results are presented as well. Clustering closely located devices which have local communication needs is a feasible and efficient way of solving the increasing data traffic requirements in the future cellular network. Reliable D2D multicast concept introduced in this paper is designed to be scalable and efficient solution for local communication needs such as file transfer and even streaming services. Due to the network involvement in controlling the local D2D communication, sufficient quality of service can be guaranteed. In addition, due to the flexible mode switching between direct and cellular modes in the integrated operation the service continuity can be provided.

Digital Television for Mobile Devices

A survey of mobile television technologies analyzes technical characteristics for each mobile TV solution, discusses specifications and standards, and presents possible future developments.

Towards Context-Aware Mobile Web 2.0 Service Architecture

The emergence of new lightweight Web technologies and the development of mobile devices leads to a situation, where the users can consume the same Web services regardless of the place, time and device. Mobile devices are equipped with networking capabilities and sensors that provide versatile context and user-community information. This information enhances the user experience as it can be used to compensate the limited means of input. We present a context-aware mobile Web 2.0 service architecture that connects user context and community information with the Web services. This convergence enables the development of device-independent services that are enriched and personalized with user context and community information. Mobile middleware may be needed for efficient delivery of this information from the mobile device to the Web services. Four novel communication models for the delivery are introduced, namely centralized control, centralized services, peer-to-peer services, and pure peer-to-peer. The purpose of the models is to offer a secure and reliable platform for creating new services. Finally, we study virtual communities and market structures of the proposed models from a multidisciplinary point of view. We claim that the selected technical model determines the prospective market structure.

Group-based content push with dynamic session startup

This paper proposes an intelligent mobile middleware utilizing group-based content push with dynamic session startup and plug-and-play features. Solution enhances the distribution of mobile content, such as game applications or multimedia files, within a peer group community. It exploits the social relationships of the user community to enable instant application downloading, installation, and licensing upon incoming connection attempt initiated by another peer group member. In the core of the middleware functionality are dynamic application identification and immediate session startup. This paper presents a use case scenario for a content push procedure. Functional and technical analysis of the novel middleware component are provided. Observations from experimental signaling system setup are mapped with estimates of end-to-end delay budget.

Augmented Reality Web Applications with Mobile Agents in the Internet of Things

Augmented reality (AR) is a promising technology for building applications in an Internet of Things (IoT) environment, utilized for visualizing information provided by IoT devices. In this paper, we enable Web-based mobile AR applications with mobile agents in a resource-oriented IoT system architecture. We present an adaptable mobile agent composition that contains the data representation logic and mappings between AR applications and system resources. Thus, mobile agents and AR application-specific data structures are exposed as global system resources. System resource linkages are considered between real-world objects and their virtual representations for mobile agent-based AR applications. The agent composition also complies with the REST principles for resource access and control system-wide. This allows dynamic runtime adaptation and addressing the device and resource heterogeneity, thus eliminating the need for application-specific communication protocols. Moreover, we utilize a Web-based mobile AR application framework, running completely in a Web browser, which facilitates straightforward AR application development. Lastly, a proof of concept mobile AR application is implemented, where a coffee maker with a visual tag is connected to a low-power resource-constrained wireless sensor network node as an IoT device. A mobile agent is injected into the IoT environment to expose the state changes of the coffee maker. Through the visual tag, AR applications are able to visualize the state changes of the coffee maker in their user interface.

GTPP: General Truncated Pyramid Peer-to-Peer Architecture over Structured DHT Networks

Hierarchical Distributed Hash Table (DHT) architectures have been among the most interesting research topics since the birth of flat DHT architecture. However, most of the previous work has merely focused on the two-tier hierarchy. In this paper, we study and analyze General Truncated Pyramid Peer-to-Peer (GTPP) architecture, the generalized version of Partially Vertical Hierarchical Architecture (PV-HA). The idea is to study whether added tiers of hierarchy can provide added value in performance and functionality. Through mathematical analysis, we demonstrate performance results in comparison to flat architecture, which helps understanding the typical characteristics of hierarchical architectures. Firstly, GTPP has slightly higher expected lookup hop count, although it can be decreased with optimizing the sub-overlay setup. However, GTPP significantly decreases the expected lookup routing latency. Secondly, GTPP has clearer and more reasonable traffic distribution among all the peers from different tiers of sub-overlays, and can work with slightly lower maintenance traffic. Thirdly, our studies indicate that two to three tiers are most suitable in most cases for GTPP, considering all the parameters.

VirtualOulu: collaborative, immersive and extensible 3D city model on the web

In this paper, we describe the creation of a photorealistic digital 3D representation of a real world city and its subsequent publication as an open and collaborative 3D virtual world on the web using an open source software platform. We present the guidelines and conventions used in the collaborative development process of the model. We report the design and implementation of the web user interface of the model that exploits on dynamic on demand (un)loading of assets during navigation to reduce memory consumption on user device. We demonstrate the extensibility of the model with example applications. We report an empirical performance evaluation of the web user interface in terms of download latencies and memory consumption, and frame rate achieved with three different types of user devices during navigation. We identify a rendering bottleneck in the current implementation and present a candidate solution for fixing it.

Power Consumption Model of a Mobile GPU Based on Rendering Complexity

This paper presents a mathematical model for predicting power consumption of a mobile device when it is rendering 3D graphics. The model is based on 3D primitives (triangles, render batches, texels), and hence is hardware agnostic. With the model, a complexity of any given 3D scene can be predicted already at a production phase without access to the actual target hardware. This paper describes how the power consumption model is derived. The model is verified with measurements of real-world content and hardware. With the given hardware, 3D data and given verification scenarios, the model is able to predict the total power consumption with an error ranging from 0.3% to 3.2%.

A Virtual World Web Client Utilizing an Entity-Component Model

The popularity of virtual worlds has increased considerably in recent years. Currently, many service providers are trying to make it easier for users to access their virtual worlds. However, accessing a virtual world typically requires a client application that needs to be versioned for each device platform and operating system configuration. Using WebGL, an interactive 3D environment can be used on a cross-platform supported web browser. In this paper, we present a system architecture that utilizes an entity-component model, and a prototype implementation of a WebGL-based virtual world client to provide a plug-in free, extensible and open source web client for 3D virtual worlds. The performance of the web client was evaluated in terms of frame rate, CPU load, memory consumption and scene processing speed. Based on the results, the performance of the web client was good on a desktop PC, but mobile hardware specific optimizations are required to provide a good user experience on mobile devices.

User Experience in Added Value Location-Based Mobile Music Service

In this paper, the user experience in added value location-based mobile music service called the City Night Life (CNL) is evaluated and analyzed. The CNL service provides recommendations about entertainment premises in the proximity by matching their music styles with the user’s personal music preferences. Entertainment premises are shown on a map interface and are marked with colors according to their match. The paper presents the components of the CNL service, the music profile, matching algorithm and the map-based user interface in a web browser. The user evaluation with 53 test users assessed the feasibility and business potential of the CNL service. Data was collected with both quantitative questionnaires and short interviews. The results indicate that the CNL service will be most useful in relatively large, unfamiliar cities. Furthermore, the matching algorithm was perceived to perform quite well.