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Given a capacitated telecommunications network with single path routing and an estimated traffic demand matrix, we aim to determine the routing path of each traffic commodity such that the whole set of paths provide an optimal network load balancing. In a recent paper, we have proposed a column generation based heuristic where, in the first step, we use column generation to solve a linear programm
The Theory of Characteristic Modes provides a convenient tool for designing multi-antennas for MIMO applications, as it enables orthogonal radiation patterns to be excited in a given antenna structure. Moreover, the frequency behavior of the modes reveals interesting wideband properties of the structure. However, the tracking of characteristic modes over frequency remains a challenge, especially w
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-
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
In this paper we present an analysis of the effects of antenna placement on the radio channel properties for Vehicle-to-Vehicle communications based on measurements performed in three different propagation scenarios; highway, urban and rural. Four omni-directional antennas were mounted at four different positions: roof, bumper, left-side mirror and inside windscreen of two standard station wagons
The ambitious goal of the upcoming IEEE 802.11ax (HEW) standard for wireless LANs (WLANs) to enhance throughput by four times (and beyond), compared with IEEE 802.11ac, demands a radical improvement of present medium access control (MAC) functionality. To this end, a promising paradigm would be a graceful migration towards new MAC protocols which incorporate higher certainty in their decisions. Ho
This paper presents a detailed description of a propagation channel measurement campaign performed in a warehouse environment and provide a comprehensive channel model for this environment. Using a vector network analyzer (VNA), we explored both Line-of-sight(LOS) and Non-Line-of-sight (NLOS) scenarios over a 2-8 GHz frequency range. We extracted both small-scale and large-scale channel parameters
We present a hierarchical traversal algorithm for stochastic rasterization of motion blur, which efficiently reduces the number of inside tests needed to resolve spatio-temporal visibility. Our method is based on novel tile against moving primitive tests that also provide temporal bounds for the overlap. The algorithm works entirely in homogeneous coordinates, supports MSAA, facilitates efficient
Governmental organisations are becoming more critically dependant on IT systems such as communication systems or patient data systems, both for their everyday tasks and their role in crisis relief activities. Therefore it is important for the organisation to analyse the reliability of these systems as part of the organisation’s risk and vulnerability analysis process. This paper presents a practic
Low-density parity-check convolutional (LDPCC) codes, also known as spatially coupled LDPC codes, can be decoded using a message passing algorithm. In order to limit decoding latency and complexity, windowed decoding can be applied. Updates within the window can be performed either in parallel or serially. However, simulation results show that uniform updating schedules do not provide the expected
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In this paper, we confirm that angle and polarization diversities are indeed the dominant diversity mechanisms of a recently proposed compact six-port MIMO antenna array, as it exhibits similar effective degree-of-freedom (EDOF) performance as that of the ideal array with co-located antenna elements evaluated in propagation scenarios with different angular spreads. Furthermore, the same approach c
We find good rate 2/3 and 3/4 convolutional codes for use with iterative decoding (turbo equalization) of coded intersymbol interference with AWGN. The method is based on the input-output bit error rate characteristic of the convolutional BCJR decoder module. An analysis leads to an equivalent minimum distance under the required intrinsic subtraction, which depends on free distance and an input-ou
The trade-off between throughput and memory constraints is a common design problem in embedded systems, and especially for streaming applications, where the memory in question usually occurs in the form of buffers for streams of data. This paper presents a methodology, based on the post-processing of dataflow execution traces, that enables designers to make principled choices in the design space f
