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Abstract in UndeterminedWe introduce Gaussian wave packets in pursuit of representations of functions, in which the representation is invariant under translation, modulation, scale,rotation and anisotropic dilation. Properties of both continuous and discrete representations are discussed. For the discrete (two-dimensional) case, we develop fastalgorithms for the application of the analysis and syn
Beamforming is an important feature of 60 GHz communications. We present an analysis of the influence of beamforming in indoor ultrawideband radio channels measured in the mm-wave 60 GHz band. The performance of narrowband and wideband direction-based beamformers is investigated in terms of improving channel metrics such as the delay spread, excess delay, and the signal-to-noise ratio (SNR). The p
A low-power high linearity CMOS G(m)-C channel select filter for WLAN/WiMax receivers in 90-nm CMOS technology is presented. To reduce power consumption a biquad cell with simple architecture and few devices is used. A simple but efficient technique is also used to improve the linearity of the filter without increasing its power consumption. The cutoff frequency of the sixth order Butterworth low-
This correspondence deals with the construction of minimum Euclidean distance precoders for multiple-input multiple-output (MIMO) systems with up to four transmit antennas. By making use of a state-of-the-art technique for optimization over the unitary group, we can numerically optimize the MIMO precoders. The correspondence then proceeds by identifying the obtained precoders as well-known lattice
This work studies the design of linear precoder codebooks for N-r x N-t MIMO channels with MMSE detection at the receiver. A natural split of precoder-design is unitary precoding and non-unitary precoding. Unitary precoding is only performing rotation of the data in a way beneficial for the channel. Non-unitary precoding additionally also uses power-loading to further improve the performance. Some
Increasing the number of persons working on quality assurance (QA) tasks, e.g., reviews and testing, increases the number of defects detected – but it also increases the total effort unless effort is controlled with fixed effort budgets. Our research investigates how QA tasks should be configured regarding two parameters, i.e., time and number of people. We define an optimization problem to answer
Realistic radio channel models are crucial for the success of vehicle-to-vehicle (V2V) system investigations. In this paper, we summarize the important parameters for V2V channel models and describe relevant measurement campaigns. Also, we develop and evaluate an ns-3 simulation model of a realistic V2V channel model that is based on measurements in Sweden. The channel model incorporates the effec
The use of duty-cycled ultralow-power wake-up receivers (WRxs) can significantly extend a node lifetime in low-power sensor network applications. In the WRx design, both the low-power operation of the WRx and the wake-up beacon (WB) detection performance are of importance. We present a system-level analysis of a duty-cycled WRx design, including an analog front end, a digital baseband, the WB stru
Vehicle-to-vehicle (V2V) communication is an enabler for improved traffic safety and congestion control. As for any wireless system, the ultimate performance limit is determined by the propagation channel. A particular point of interest is the shadowing effect of large vehicles such as trucks and buses, as this might affect the communication range significantly. In this paper we present measuremen
A 12 GHz PLL with digital output phase control has been implemented in a 90 nm CMOS process. It is intended for LO signal generation in integrated phased array transceivers. Locally placed PLLs eliminate the need of long high frequency LO routing to each transceiver in a phased array circuit. Routing losses are thereby reduced and the design of integrated phased array transceivers becomes more mod
In this paper we study an optimization problem relevant for wireless networks. In such networks links are subject to capacity disruptions caused by changing weather/channel condition that force to adapt the modulation and coding schemes to the observed condition. To cope with this issue in network optimization, we need to consider a so called link availability set A and a routing strategy that can
This paper has evaluated the overhead requirements for IOTA pulse shaping filters employed in faster-than-Nyquist multicarrier systems. Faster-than-Nyquist signaling has shown the promise of improving bandwidth efficiency, but comes at the cost of increased processing complexity in the transceiver. The IOTA filter being one of the blocks contributing for the processing overhead, different architec
Spatially-coupled regular LDPC code ensembles have outstanding performance with belief propagation decoding and can perform arbitrarily close to the Shannon limit without requiring irregular graph structures. In this paper, we are concerned with the performance and complexity of spatially-coupled ensembles with a rate-compatibility constraint. Spatially-coupled regular ensembles that support rate-
Abstract in UndeterminedAbout a hundred studies on traceability recovery have been published in software engineering fora. In roughly half of them, software artifacts developed by students have been used as input. To what extent student artifacts differ from industrial counterparts has not been fully explored in the literature. We conducted a survey among authors of studies on traceability recover
Vehicles in the future are anticipated to have the ability to communicate and exchange useful information in order to avoid collisions. However, for this cooperation to be possible all vehicles will have to be equipped with compatible wireless IEEE 802.11p modules that implement intelligent transport systems operating in the 5 GHz frequency band standard (ITS-G5 or WAVE). During the implementation
We deal with a natural integer-linear programming formulation of the routing and spectrum allocation (RSA) problem in elastic optical networks. We focus on strengthening the formulation with valid inequalities (cuts). For this purpose we apply clique inequalities that proved to be useful in other applications of this kind. We develop and combine a clique cut generation procedure with a column gene
Changes in evolving software systems are often managed using an issue repository. This repository may contribute to information overload in an organization, but it may also help navigating the software system. Software developers spend much effort on issue triage, a task in which the mere number of issue reports becomes a significant challenge. One specific difficulty is to determine whether a new
With the introduction of new cellular phone standards with increased modulation complexity and signal bandwidth, the design of efficient transmitters will be a major challenge. With this in mind a number of switched mode transmitter architectures are described, both polar and Cartesian ones. The most promising candidates use a combination of supply voltage modulation and other techniques, such as
