Elektrobit

About: Elektrobit is a company organization based out in Espoo, Finland. It is known for research contribution in the topics: MIMO & Communication channel. The organization has 262 authors who have published 327 publications receiving 5633 citations.

WINNER II Channel Models

Abstract: This chapter contains sections titled: Introduction Modelling Considerations Channel‐Modelling Approach Channel Models and Parameters Channel Model Usage Conclusion Acknowledgements References

Survey of channel and radio propagation models for wireless MIMO systems

Abstract: This paper provides an overview of the state-of-the-art radio propagation and channel models for wireless multiple-input multiple-output (MIMO) systems. We distinguish between physical models and analytical models and discuss popular examples from both model types. Physical models focus on the double-directional propagation mechanisms between the location of transmitter and receiver without taking the antenna configuration into account. Analytical models capture physical wave propagation and antenna configuration simultaneously by describing the impulse response (equivalently, the transfer function) between the antenna arrays at both link ends. We also review some MIMO models that are included in current standardization activities for the purpose of reproducible and comparable MIMO system evaluations. Finally, we describe a couple of key features of channels and radio propagation which are not sufficiently included in current MIMO models.

Millimeter-Wave Propagation Channel Characterization for Short-Range Wireless Communications

Abstract: This paper presents and analyzes the results of millimeter-wave 60-GHz frequency range propagation channel measurements that are performed in various indoor environments for continuous-route and direction-of-arrival (DOA) measurement campaigns. The statistical parameters of the propagation channel, such as the number of paths, the RMS delay spread, the path loss, and the shadowing, are inspected. Moreover, the interdependencies of different characteristics of the multipath channel are also investigated. A linear relationship between the number of paths and the delay spread is found, negative cross correlation between the shadow fading and the delay spread can be established, and an upper bound exponential model of the delay spread and the path loss is developed to estimate the worst case of the RMS delay spread at given path loss. Based on the DOA measurements that are carried out in a room [line of sight (LOS)] and in a corridor with both LOS and nonline-of-sight (NLOS) scenarios, radio-wave propagation mechanisms are studied. It is found that considering the direct wave and the first-order reflected waves from smooth surfaces is sufficient in the LOS cases. Transmission loss is very high; however, diffraction is found to be a significant propagation mechanism in NLOS propagation environments. The results can be used for the design of 60-GHz radio systems in short-range wireless applications.

A multiple case study on the impact of pair programming on product quality

Abstract: Pair programming is a programming technique in which two programmers use one computer to work together on the same task. There is an ongoing debate over the value of pair programming in software development. The current body of knowledge in this area is scattered and unorganized. Review shows that most of the results have been obtained from experimental studies in university settings. Few, if any, empirical studies exist, where pair programming has been systematically under scrutiny in real software development projects. Thus, its proposed benefits remain currently without solid empirical evidence. This paper reports results from four software development projects where the impact of pair programming on software product quality was studied. Our empirical findings appear to offer contrasting results regarding some of the claimed benefits of pair programming. They indicate that pair programming may not necessarily provide as extensive quality benefits as suggested in literature, and on the other hand, does not result in consistently superior productivity when compared to solo programming.

Online Signature Verification With Support Vector Machines Based on LCSS Kernel Functions

Abstract: In this paper, a new technique for online signature verification or identification is proposed. The technique integrates a longest common subsequences (LCSS) detection algorithm which measures the similarity of signature time series into a kernel function for support vector machines (SVM). LCSS offers the possibility to consider the local variability of signals such as the time series of pen-tip coordinates on a graphic tablet, forces on a pen, or inclination angles of a pen measured during a signing process. Consequently, the similarity of two signature time series can be determined in a more reliable way than with other measures. A proprietary database with signatures of 153 test persons and the SVC 2004 benchmark database are used to show the properties of the new SVM-LCSS. We investigate its parameterization and compare it to SVM with other kernel functions such as dynamic time warping (DTW). Our experiments show that SVM with the LCSS kernel authenticate persons very reliably and with a performance which is significantly better than that of the best comparing technique, SVM with DTW kernel.