Digital healthcare applications are part of the Industry 4.0 which is based on smart devices and trustworthy communications technology. The concept of Digital-care is based on providing a permanent connection between the patient and the medical department (medical staff), and the ability to analyze the patient's data automatically. With the existence of modern wireless networks, which support, for example, the Internet of Things (IoT), cloud computing, virtual reality, virtual machine, and low-power wireless networks it is possible to achieve this permanent connection while maintaining confidentiality and privacy of patient data. Digital-care applications rely on essential features, such as ensuring availability, almost zero delays, adequate storage capacity, and data protection. To achieve this term, many challenges must be solved. This paper presents a comprehensive concept of Digital-care applications, the wireless network infrastructure required by those applications, the role of current and future wireless networks in their prospects, and the challenges they face. Moreover, this paper also provides a comprehensive discussion of the proposed solutions that can be used on modern wireless networks for adoption.

Existing researches on the theoretical analysis for Proportional Fair (PF) scheduling are mostly based on the full buffer assumption while the user always has a bursty traffic in reality. In this paper, an analytical framework for PF scheduling in an Orthogonal Frequency Division Multiple Access (OFDMA) wireless network is proposed, and the user traffic is set to follow a poisson arrival process. Detailed analysis for each user's Resource Block (RB) competition status is carried out, and an M/M/1 queuing model is adopted for the packet transmission process of each user, with which the analytical expressions for user throughput and packet latency are obtained. Simulation in a single-cell OFDMA network is carried out and the comparision between simulation and analysis results confirms the accuracy of our analysis.

There are an increasing number of information sources and services around us enabling new ways of interacting with our everyday environment. Examples include intelligent devices, sensors embedded in the environment and the emerging Internet-of-Things. Simultaneously users are becoming increasingly involved as information providers and consumers by means of Web 2.0 and social media. While these areas have gained a lot of attention recently and while the research on Digital Ecosystems has also dealt with these phenomena separately there seems to be need for research on the rich and complex ecosystem combining the sensor-based information sources with Web 2.0 and mobile services. In this paper, we propose a digital ecosystem architecture for ubiquitous campus Living Lab innovation platform which combines sensor based embedded system and social media based on the international collaboration between two long-term university Living Lab research projects in Finland and China. The paper focuses on the architecture design and implementation of the platform, and also discusses its implications to digital ecosystem research.

In recent years, we have seen the rise of Web 2.0, where users become co-creators and software turns into services. While Web 2.0 technologies and concepts have been studied separately, we suggest that the digital ecosystem they form together and the ways in which users interact with it in social contexts have not been made explicit. In this paper, we provide a conceptual model of a community and a digital ecosystem for boosting user-driven service business. To construct such a model, we first identify the key actors and their interactions by applying use case modelling. Based on that, conceptual modelling is used to sketch an illustrative model of the overall ecosystem. Finally, we use the field of bioinformatics to evaluate the model and to propose ideas for boosting user-driven service business in that field as well.

This paper introduces two methods for the integration of a dynamically steered beamforming filter with acoustic echo cancellation (AEC) and adaptive generalized sidelobe canceler (GSC) based beamforming methods. We evaluate the performance of a beamforming system with moving and changing source positions. Individual contributions of adaptive beamforming and steering independent AEC processing methods are evaluated for high level echo cancellation in a typical office environment. The results show that the proposed adaptive beamforming method increases the overall AEC performance even if GSC adaptation would be disturbed by dynamic beam steering.

This paper presents the results of a co-existence study investigating the impact of ultra wideband (UWB) interference on IEEE802.11b and Bluetooth networks. Results are based on the experimental test measurements made at the University of Oulu, Finland using simple high power UWB transmitter prototypes as interference sources. Preliminary results showed that, under the extreme conditions of this experiment, both IEEE802.11b and Bluetooth networks will slightly suffer from the existence of several high proximity UWB signals. In our study, several high power UWB transmitters that greatly exceed the FCC radiation regulations have been used, and the measurement settings presents the worst case scenario due to the very short distance between the interferers and the victim system. Effectively our study indicates the use of hundreds of FCC compatible UWB devices at a same space.

This paper studies in-band interference of different kind of ultra wideband (UWB) signals. UWB frequency spectra are produced by using several types of narrow pulse waveforms, all based on the Gaussian pulse. Due to the extremely wide bandwidth, these signals spread over the frequency bands allocated to other radio systems. In-band interference power is calculated over the IF bandwidths of two victim receivers as a function of pulse width. Also, the signal attenuation with distance is presented. The victim systems under the study are GPS (L1-band) and GSM900. Based on the results, the 3/sup rd/ derivative of a Gaussian pulse seems to be the best choice, from the interference point of view, among the waveforms included in this study. It causes less interference than the Gaussian pulse or Gaussian doublet if the pulse widths are shorter than 1 ns. The system utilizing the direct sequence concept caused less in-band interference power than the system utilizing time hopping amongst all waveforms studied. The studied UWB systems are based on bi-phase baseband data modulation.

This paper evaluates the level of interference caused by different ultra-wideband (UWB) signals to other various radio systems, as well as the performance degradation of UWB systems in the presence of narrowband interference and pulsed jamming. The in-band interference caused by a selection of UWB signals is calculated at GSM900, UMTS/wideband code-division multiple-access (WCDMA), and Global Position System (GPS) frequency bands as a function of the UWB pulsewidth. Several short-pulse waveforms, based on the Gaussian pulse, can be used to generate UWB transmission. The two UWB system concepts studied here are time hopping and direct sequence spread spectrum. Baseband binary pulse amplitude modulation is used as the data modulation scheme. Proper selection of pulse waveform and pulsewidth allows one to avoid some rejected frequency bands up to a certain limit. However, the pulse shape is also intertwined with the data rate demands. If short-pulses are used in UWB communication the high-pass filtered waveforms are preferred according to the results. The use of long pulses, however, favors the generic Gaussian waveform instead. An UWB system suffers most from narrowband systems if the narrowband interference and the nominal center frequency of the UWB signal overlap. This is proved by bit-error rate simulations in an additive white Gaussian noise (AWGN) channel with interference at global system for mobile communication (GSM) and UMTS/WCDMA frequencies.

We introduce a polynomial filter structure for filter-and-sum beamforming applied to a microphone array application. The structure is a multidimensional extension of the well known Farrow structure, which has mainly been used for fractional delay filtering and interpolation of I-D signals. The proposed method enables an easy, smooth and efficient control of the beamforming filter characteristics by adjusting only a single control variable, e.g., for dynamic beam steering. The optimization method for polynomial beamforming filter design is presented and illustrated with simulations of beamforming filter characteristics. The design example is given for a linear array of four omni-directional microphones and a polynomial FIR filter with 20-tap delay lines.

This paper explains the realization and the performance of a digital stepping correlator in a wideband radio channel measurement system. Radio channel sounding is based on the estimation of the radio channel by use of maximum length sequence (m-sequence) as an effective sounding signal. Signal is detected using the stepping correlator receiver. The received signal is not converted to the baseband but the sampling is done direct from the IF-frequency. Digital implementation gives also a possibility to use a windowing property when those parts of the impulse responses that do not contain signal power are abandoned during measurements. The windowing enables high radio channel sampling rates.

The multipath characteristics of the wireless local loop (WLL) channel were studied over both short and long time periods in urban and sub-urban high-rise and small-house environments. Wideband measurements were performed at a centre frequency of 1.3 GHz with a sliding correlation measurement system using a chip rate of 15 MHz. The receiver was situated at regular cellular base stations, and the transmitter with an omnidirectional antenna was moved to several rooms in different buildings around the base station sites. During the recordings the movement of people in the measurement rooms was restricted. The short-term results show a high degree of similarity in the multipath characteristics of the WLL channel in urban and sub-urban high-rise environments. The maximum measured values of delay spreads for the urban and suburban high-rise environments were 410 ns and 360 ns, respectively. For the sub-urban small-house environment the data indicate lower values of delay spread. The channel was shown to be very slowly fading, being in most situations essentially static over short time periods of the order of several tens of seconds. The variation of the channel characteristics over long time periods was shown to be significant.