Sökresultat

An LTE-enabled smartphone is a software-defined radio system that must cover a large number of frequency bands with different duplex differences. A proposed adaptive wideband duplexer needs a circulator to create the required initial isolation. To replace this an LC-based tunable low-isolation device is presented in this paper, providing the required tuning range for LTE Band I, II, III and VII. T

Correct estimation of symbol timing, Carrier Frequency Offset (CFO), and Signal-to-Noise Ratio (SNR) is crucial in Orthogonal Frequency Division Multiplexing (OFDM) communication. Typically, high estimation accuracy is desired, but often comes with increased complexity. Which has a direct repercussion in energy consumption. In this article, an architecture based on Sign-Bit estimation with low com

This study describes a high throughput constant envelope (CE) pre-coder for Massive MIMO systems. A large number of antennas (M), in the order of 100s, serve a relatively small number of users (K) simultaneously. The stringent amplitude constraint (only phase changes) in the CE scheme is motivated by the use of highly power-efficient non-linear RF power amplifiers. We propose a scheme that compute

Test managers have to repeatedly select test cases for test activities during evolution of large software systems. Researchers have widely studied automated test scoping, but have not fully investigated decision support with human interaction. We previously proposed the introduction of visual analytics for this purpose. Aim: In this empirical study we investigate how to design such decision suppor

A Multi-band CMOS front-end was designed and fabricated in a 0.13μm CMOS process. The front-end employs a common-gate low noise amplifier (LNA) with capacitive cross coupling (CCC) technique and a double balanced mixer. The band selection is performed by switching capacitors in and out of the LNA load, changing the resonance frequencies ranging from 2.5GHz to 4.5GHz in 16 different frequency bands

Architectural improvements for a multicarrier faster-than-Nyquist (FTN) decoder are presented in this work. A previously designed FTN decoder has been optimized during implementation, especially with respect to memory considerations to reduce area and power. The memory optimized architecture achieves 28.7% savings in overall chip area and provides 43.8% savings in the estimated power compared to t

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.

There is a gap between software testing research and practice. One reason is the discrepancy between how testing research is reported and how testing challenges are perceived in industry. We propose the SERP-test taxonomy to structure information on testing interventions and practical testing challenges from a common perspective and thus bridge the communication gap. To develop the taxonomy we fol

The fast correlation attack is a general cryptanalytic attack directed at stream ciphers and is related to the decoding of low-density parity-check (LDPC) codes. In this paper, we improve the message passing algorithm by exploiting the fact that the sum of an arbitrary number of initial state variables, called a fixed point, can be written as the sum of only a few other variables. This will result

This paper presents an energy-efficient sorted QR decomposition (SQRD) processor for 3GPP LTE-Advanced (LTE-A) systems. The processor adopts a hybrid decomposition scheme to reduce computational complexity and provides a wide-range of performance complexity trade-offs. Based on the energy distribution of spatial channels, it switches between the brute-force SQRD and a low-complexity group-sort QR-

The use of household electricity and domestic hot water has been measured for 72 apartments in an apartment building located in the south of Sweden. The measurements were carried out with samples every 6 s, a tenfold increase in resolution compared to available published data, during a measurement period of five days, in the winter season, including a weekend. The influence of the time resolution

We sought to determine whether specific characteristics of vertebral fractures in elderly men are associated with low bone mineral density (BMD) and osteoporosis. Mister osteoporosis Sweden is a population based cohort study involving 3014 men aged 69 to 81 years. Of these, 1427 had readable lateral radiographs of the thoracic and lumbar spine. Total body (TB) BMD (g/cm²) and total right hip (TH)

Sustainability degree programs in higher education have proliferated with the emergence of sustainability as a recognized academic field. This study evaluated the curricula of English-language programs granting degrees in sustainability by analyzing 27 bachelor's and 27 master's sustainability programs based on their (1) curricular structure, in terms of the proportion of core versus elective cour

An adaptive matching network provides a number of states between which it can be reconfigured. At a certain frequency, the matching network transforms a reference impedance to different impedances for the different states. The circuit will be able to match those impedances perfectly to the reference impedance, and impedances close to those will also be fairly well matched. The matching will, howev

Just as the wireless communication technology develops further to achieve higher performance, new application areas emerge to challenge its limits. Vehicular ad hoc networks are one of these areas; and emergency situation warning is one of their most popular potential applications since traffic safety is a real concern for everyone. Due to the life-critical nature of emergency applications, howeve

PPARGC1A and PPARGCB encode transcriptional coactivators that regulate numerous metabolic processes. We tested associations and treatment (i.e. metformin or lifestyle modification) interactions with metabolic traits in the Diabetes Prevention Program, a randomised controlled trial in persons at high risk of type 2 diabetes.

Future mobile terminals are expected to support an ever increasing number of Radio Access Technologies (RAT) concurrently. This imposes a challenge to terminal designers already today. Software Defined Radio (SDR) solutions are a compelling alternative to address this issue in the digital baseband, given its high flexibility and low Non-Recurring Engineering (NRE) cost. However, the challenge stil

Finding optimal routes and spectrum allocation in flexgrid optical networks, known as the RSA problem, is an important design problem in transport communication networks. The problem is NP -hard, and its intractability becomes profound when network instances with several tens of nodes and several hundreds of demands are to be solved to optimum. In order to deal with such instances, large-scale opt

Consumption of sugar has been relatively high in the Nordic countries; the impact of sugar intake on metabolic risk factors and related diseases has been debated. The objectives were to assess the effect of sugar intake (sugar-sweetened beverages, sucrose and fructose) on association with type 2 diabetes, cardiovascular disease and related metabolic risk factors (impaired glucose tolerance, insuli