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Radio based localization is an active research topic with a wide range of applications. In this paper, we focus on localization of a radio receiver equipped with an inertial measurement unit. The localization is performed while simultaneously constructing a map of the small scale fading pattern in the local radio environment. The map in our case is a ray-trace-based multipath channel model. This s
The future of cellular radio ICs lies in the integration of an ever-increasing number of bands and channel bandwidths. This paper presents a transceiver together with the associated discrete front-end components. The transceiver supports 4 EDGE bands and 9 WCDMA bands (l-VI and Vlll-X), while the radio can be configured to simultaneously support the 4 EDGE bands and up to 5 WCDMA bands: 3 high ban
The paper examines the impact of Rician fading on the orthogonality of dual-polarized MIMO channels in a measured urban macrocellular scenario. The measurements confirm the previous finding that the Rician
Using antenna arrays for direction of arrival (DoA) estimation and source localization is a well-researched topic. In this paper, we analyze virtual antenna arrays for DoA estimation where the antenna array geometry is acquired using data from a low-cost inertial measurement unit (IMU). Performance evaluation of an unaided inertial navigation system with respect to individual IMU sensor noise para
This paper presents an efficient technique to enhance the isolation between two closely spaced PIFAs for MIMO mobile terminals. The proposed decoupling method is based on a T-shape slot impedance transformer and it enables an inter-PIFA spacing of 1 mm to be achieved. The 10 dB impedance bandwidth and 20 dB isolation bandwidth cover the 2.4 GHz WLAN band (2.4-2.48 GHz), with a maximum isolation of
Elasticity is the ability of a cloud infrastructure to dynamically change the amount of resources allocated to a running service as load changes. We build an autonomous elasticity controller that changes the number of virtual machines allocated to a service based on both monitored load changes and predictions of future load. The cloud infrastructure is modeled as a G=G=N queue. This model is used
Data volumes in communication networks increase rapidly. Further, usage of social network applications is very wide spread among users, and among these applications, Facebook is the most popular. In this paper, we analyse user demands patterns and content popularity of Facebook generated traffic. The data comes from residential users in two metropolitan access networks in Sweden, and we analyse mo
In this paper we describe a systematic study on long-term evolution of residential broadband Internet traffic covering 5 calendar years from June 2007 to May 2011. The traffic evolution is characterized both in the term of the total traffic volume, as well as the traffic volumes and shares for different application categories (file sharing, video streaming etc.), with the focus on comparing the tr
Excitation of the chassis enables single-antenna terminals to achieve good bandwidth and radiation performance, due to the entire chassis being utilized as the main radiator. In contrast, the same chassis excitation phenomenon complicates the design of multiple antennas for MIMO applications, since the same characteristic mode of the chassis may be effectively excited by more than one antenna, lea
Electromagnetic vector spherical waves have been used recently to model antenna-channel interaction and the available degrees of freedom in MIMO systems. However, there are no previous accounts of a method to estimate spherical wave coefficients from channel measurements. One approach for this, using a 3D positioner, is presented and analyzed in this letter. Measurement results are presented and d
Base station (BS) cooperative transmission is a promising technique to improve spectral efficiency of cellular systems, using which the channels become asymmetric in average gain. In this paper, we study the impact of the asymmetric channel gains on the performance of coherent cooperative transmission systems, when minimum mean square error (MMSE) and least square (LS) channel estimators are appli
The Theory of Characteristic Modes (TCM) has been applied to design high-performance MIMO antennas for mobile terminals. However, existing studies focus on free-space (FS) performance, which is mostly irrelevant in real usage. This paper investigates the performances of two TCM-based MIMO terminal antenna designs in 7 realistic user scenarios for frequencies below 1 GHz. Full-wave simulation resul
Training studies in children have suggested that endurance training can give enlargement of cardiac dimensions. This relationship has not been studied on a population-based level in young children with objective methods. A cross-sectional study was made of 248 children (140 boys and 108 girls), aged 8-11 years, from a population-based cohort. Left ventricular end-diastolic diameter (LVDD) and left
Traffic measurements in broadband access networks are crucial from several points of view. A better understanding of traffic patterns can lead to more efficient network design, which leads to energy and cost savings for the operator and improved end user services. This paper reports on selected traffic measurement results from the Celtic TRAMMS project. The measurements were performed in broadband
This paper presents a 3rd-order, 3-bit continuous time (CT) Delta-Sigma modulator for an LTE radio receiver. By adopting a return-to-zero (RZ) pulse in the innermost DAC, the modulator shows a reduced sensitivity to loop-delay variations, and the additional loop delay compensation usually needed in CT modulators can be omitted. The modulator has been implemented in a 65nm CMOS process, where it oc
With increasing usage of the Internet, energy consumption of network equipment has become a crucial challenge from both an economic and an environmental point of view. This paper combines users’ behavior of accessing the network with energy saving algorithms for energy-aware network equipment, and investigates potential energy savings in the access network. The study is based on a set of traffic d
Internet traffic from a fibre based residential access network is investigated concerning traffic volumes and link load. Also the cost of the services is analyzed. We show that 1 Mbps accesses subscribers maintain high loads, and that the price they pay per GB used is five times higher than the one paid by 100 Mbps access subscribers.
