Recent advances in peer-to-peer (P2P) technologies will enable users to establish ubiquitous connectivity among their personal networked devices and those of others. Building on top of such technologies, we propose a platform of middleware and user interaction tools, called MyNet, that allows everyday users to easily and securely access and share with others their devices, services, and content, without requiring expertise or centralized service support. MyNet offers a more immediate and responsive alternative to the current web-based paradigm of personal and social networking, because it allows users’ distributed services and content to be accessed and shared in real-time as they are produced, directly from their personal devices. In this paper, we describe the MyNet system architecture, including secure resource discovery, service management, security framework, and the user interaction tools for building personal and social networks and sharing resources over them. We also present our proof-of-concept implementation, including mobile devices and our tests with real users.

While pure Web-based services and P2P technologies are popular for personal and social networking, they both have inherent limitations. A hybrid P2P/Infrastrucutre approach could leverage strengths and address limitations of both paradigms. In this paper we propose such a platform based on MyNet, our P2P personal and social networking system. The new hybrid architecture enhances the properties of pervasive access, security and ease of use found in MyNet through the introduction of infrastructure-hosted MyNet Virtual Devices (MVD). MVDs act as userspsila personal devices, but also host MyNet-aware Internet services (MaIS), proxies for 3rdparty Internet services. A proof-of-concept prototype and user results are presented to showcase key system features.

Abstract—Mobile devices are increasingly assuming an important role in “smart home ” network environments. Although their computing, storage and networking capabilities have evolved significantly, these devices remain power-constrained and, therefore, need to actively take measures to minimize their power consumption. In this paper, we propose a Network Connectivity Power Saving (NC-PS) mechanism for mobile devices in Digital Living Network Alliance (DLNA) home networks, which allows them to conserve power without compromising their higher-layer functionality. The proposed mechanism introduces a level of indirection that abstracts the low-level low-power support of different wireless bearers and exposes a uniform interface to higher-layer entities, such as applications and Universal–Plugand-Play (UPnP) agents. We define four abstract NC-PS modes and we describe their mapping in the case of Bluetooth, a common wireless bearer for mobile devices, now supported in DLNA.

A crucial challenge to enabling multi-device home networked systems is providing a way for non-expert consumers to combine, configure and control the available functions. Unfortunately, the typical consumers find it difficult to perform tasks using even stand-alone programmable CE devices; programming and controlling smart homes involving a number of connected devices and services represents a significantly bigger challenge. We present our architecture for end-user programming of novel application concepts in smart homes. Our architecture has an end-user layer, a scripting layer, a semantic adaptation layer, a distributed middleware layer and a local system layer. We describe the overall end-user's process for creating applications. We discuss a part of our implementation that automatically discovers and composes devices into arrangements that satisfy the user's goal.

This paper presents IntuiSec, a framework for intuitive user interaction with smart home security using mobile devices. The design approach of IntuiSec is to introduce a level of indirection between the user-level intent and the system-level security infrastructure. This layer of indirection, implemented by a collection of distributed middleware and user-level tools, exposes only concepts and real-world metaphors that are intuitive to non-expert users and translates their intent to the necessary underlying security settings. The IntuiSec framework presents the user with intuitive steps for setting up a secure home network, establishing trusted relationships between devices, and granting temporal, selective access for both home occupants and visitors to devices within the smart home.

In this paper, we present our experience in implementing an experimental end-node architecture and communications middleware that enables devices to (a) create and maintain ad-hoc connectivity in the absence of infrastructure support, (b) heal IP network partitions and resume active TCP sessions during intermittent connectivity, (c) detect network infrastructure (e.g. access points) when available and use it, and (d) discover devices and services currently attached to the network. In broader terms, our communications middleware includes a connection manager (CM) that provides and maintains the link-level and IP infrastructures and heal network partitions as they occur, arid a session manager (SM), which provides end-to-end active TCP-session support against intermittent connectivity and IP address changes. Finally, we provide some experimental results from a working implementation of our communications middleware on Linux devices and results from its support, of two example distributed applications, namely a distributed file browser and a multiplayer game

In this paper, we present a new tree-based Bluetooth (BTH) scatternet formation and healing protocol called GC-tree, Our protocol enables group collaboration, e.g. wireless ad-hoc meetings, where individuals bring piconets with their devices in a scatternet to collaborate. We present experimental performance results from a prototype implementation using uff-the-self BTH v1.1 hardware and Linux-based devices. Finally, we complement our experimental results with a realistic simulation model

This paper investigates a real-world problem termed "Bluetooth (BTH) pollution", which is expected to become commonplace as the mass deployment of BTH devices continues. BTH pollution is caused by the presence of a large number of noncooperating BTH devices within the same radio coverage area, which beyond introducing radio interference, also affect each other's basic BTH operations such as discovery, paging and connection setup. The overall result can be a significant slow-down in BTH networking operations, e.g. ad-hoc network formation and healing. We believe the effect of BTH pollution is largely ignored in the BTH ad-hoc networking literature. In this paper we provide an insight on the causes of this problem, as well as simulation and experimental results that illustrate it. Finally, we propose a solution to accelerate BTH ad-hoc networking based on the use of the class of device (CoD) information specified in the BTH standard

Multicarrier code-division multiple access (MC-CDMA) combines multicarrier transmission with direct sequence spread spectrum. Different approaches have been adopted which do not assume a perfectly known channel. We examine the forward-link performance of decision-directed adaptive detection schemes, with and without explicit channel estimation, for MC-CDMA systems operating in fast fading channels. We analyze theoretically the impact of channel estimation errors by first considering a simpler system employing a threshold orthogonality restoring combining (TORC) detector with a Kalman channel estimator. We show that the performance deteriorates significantly as the channel fading rate increases and that the fading rate affects the selection of system parameters. We examine the performance of more realistic schemes based on the minimum mean square error (MMSE) criterion using least mean square (LMS) and recursive least square (RLS) adaptation. We present a discussion which compares the decision-directed and pilot-aided approaches and explores the tradeoffs between channel estimation overhead and performance. We find that there is a fading rate range where each method provides a good tradeoff between performance and overhead. We conclude that the MMSE per carrier decision-directed detector with RLS estimation combines good performance in low to moderate fading rates, robustness in parameter variations, and relatively low complexity and overhead. For higher fading rates, however, only pilot-symbol-aided detectors are appropriate.

The remarkable performance of turbo codes for low SNRs in AWGN channels has encouraged the application of turbo codes to systems operating in different kind of channels. In this paper we consider an IS-95-based CDMA system operating in a multipath Rayleigh fading channel. We replace the convolutional encoder by a parallel and a serial turbo encoding scheme, and by a serial concatenation of an outer convolutional and an inner parallel turbo code, and instead of the Viterbi decoder we use iterative decoding based on the MAP algorithm. We perform BER and FER comparisons by varying system parameters such as the constraint length of the component convolutional codes, the interleaver lengths, and the wireless channel fading rate. The results obtained show that the concatenated schemes outperform the more complex convolutional scheme even for relatively short interleaving lengths, especially when FER is the desired figure of merit.

Multi-carrier CDMA (MC-CDMA) is a hybrid multiple access scheme combining multi-carrier modulation (MCM or OFDM) with direct sequence spread spectrum (DS-SS). Although a common assumption in the analysis of the performance of the various MC-CDMA detectors is that they have perfect knowledge of the fading channel, this assumption is no longer valid as the fading rate (Doppler spread) of the channel increases. We examine the performance of various forms of the minimum mean square error (MMSE) detector operating in a fast fading Rayleigh channel described by a Gauss-Markov state-space model. We show that, although adaptive detection based on the LMS and RLS algorithms is possible without explicit channel estimation, a low complexity detector, termed MMSE per carrier, combined with an RLS channel estimator can achieve better performance as well as increased robustness to the selection of the adaptation parameters.