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The post-failure convergence of shortest path routing (SPR) protocols used in IP networks can be too slow to meet the restrictive requirements (i.e. maximum allowable delay, jitter, etc.) of the multimedia services and therefore new protection/restoration mechanisms combined with IP routing are of interest. The article addresses the optimization of three potential rerouting mechanisms based on the
In this paper we establish a geometry-based stochastic ultra-wideband channel model for outdoor infostations scenarios. We statistically describe the location and strength of clusters of scatterers, as well as the shape and width of visibility and shadowing regions. We also separately model diffuse radiation (which cannot be explained by the scatterer components), and show that its fading statisti
Effective requirements engineering (RE) can support efficient development of successful products. However, assessing and improving how RE supports its context, i.e. the development life cycle, is non-trivial since many different roles and factors are involved over a long period of time. Project retrospectives may support project teams in reflecting on how requirements are agreed upon and communica
Consumers are pushing for higher data rates to support more services that are introduced in mobile applications. As an example, a few years ago video-on-demand was only accessed through landlines, but today wireless devices are frequently used to stream video. To support this, more flexible network solutions have merged in 4G, introducing new technical problems to the mobile terminal. New techniqu
In this paper, we introduce the concept of spatially coupled turbo codes (SC-TCs), as the turbo codes counterpart of spatially coupled low-density parity-check codes. We describe spatial coupling for both Berrou et al. and Benedetto et al. parallel and serially concatenated codes. For the binary erasure channel, we derive the exact density evolution (DE) equations of SC-TCs by using the method pro
A compact dual-element antenna suitable for ultrawideband (UWB) MIMO operation is proposed in this work. The size of the antenna is 25 mm by 40 mm and it covers the lower UWB band of 3.15-5.15 GHz. Apart from the inherent wideband isolation obtained through the different angle and polarization characteristics in the radiation patterns of the individual elements, the gap between the two antenna ele
This paper presents a low-complexity energy efficient channel pre-processing update scheme, targeting the emerging 3GPP long term evolution advanced (LTE-A) downlink. Upon channel matrix renewals, the number of explicit QR decompositions (QRD) and channel matrix inversions are reduced since only the upper triangular matrices R and R^-1 are updated, based on an on-line update decision mechanism. Th
The goal of the presented work is to provide support for software requirements engineering domain experts in modeling combinatorial optimization problems that arise in requirements prioritization and release planning. A Domain-Specific Language (DSL), called reqT/CSP, is presented that integrates constraints modeling with requirements modeling. The DSL is embedded in the object-functional Scala pr
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, using a 3D positioner, is presented in this letter, both in theory and practice. Measurement results are present
Multipath routing of traffic demands, known also as bifurcated routing or load sharing, has been studied for various telecommunication networks for a long time. An advantage of multipath routing is that it gives a demand the opportunity to use multiple paths through the network to send its traffic. In a single-commodity situation, this benefit can be clearly seen. When multiple demands (multi-comm
