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In this article we present a survey of routing methods in Optical Burst Switching (OBS) networks We begin with a description of routing approaches and follow the discussion with a detailed classification of routing algorithms in OBS. Afterwards, we discuss common OBS network loss models that are frequently used in routing optimization. As examples of such application, we present a linear and a non
We investigate antenna correlation of an M-antenna massive multiple-input multiple-output (MIMO) setup with the purpose of obtaining a low-rank representation of the instantaneous massive MIMO channel. Low-rank representation bases using short-term and long-term antenna correlation statistics are defined, and their performance is evaluated with data sets obtained from channel measurements in both
Coordinated Multi Point (CoMP) transmission and reception techniques are used in order to improve the performance of single or multiple cells in wireless systems. A system using CoMP techniques is capable of jointly optimizing its transmission and/or reception and, hence, achieving higher performance. In this work, performance evaluation of three CoMP techniques are performed based on simulations
The possibility of using radio over fiber (RoF) analog transmissions to characterize the wireless propagation channel of distributed antenna systems is investigated. In particular, the coherence time of kilometer-long, fiber-based networks is analyzed. Joint measurements of the phase noise of parallel links to the same site (intra-site) and to different sites (inter-site) in such a network are pre
A fully integrated remote antenna unit (RAU) intended for fiber-fed distributed multiple-input multiple-output systems is presented. The circuit is designed for narrowband (60 MHz) time-division duplex systems, where an IF over fiber approach is chosen to facilitate the use of low-cost optical components and integrated photodetectors. A novel antenna switch control scheme is introduced, which enab
Massive MIMO is a promising technology for the coming 5G wireless systems. In this paper, a programmable baseband processor specifically designed for uplink symbol detection targeting massive MIMO is presented with a novel matrix inversion method proposed to obtain more precise and efficient computation. Including a microcode controlled channel preprocessing unit and a pipelined detection unit, th
This paper serves as an overview to the special session Circuits and Systems for 5G on IEEE International Conference on ASIC (ASICON) 2015. More specifically, we introduce two of enabling technologies for the coming 5G wireless era, namely massive multiple-input multiple-output (MIMO) technique and advanced coding techniques such as polar codes. Massive MIMO is a relatively new wireless communicat
The objective of this paper is to design a compressor for silicon debug that is suitable in an industrial Nexus environment. The compressor must operate in real-time and must be lossless. Important for the compressor is high compression ratio, low hardware cost and high throughput. We implemented the compression on an FPGA and we compared our implementation in terms of throughput and hardware cost
Further exploitation of the spatial domain, as in Massive MIMO (MaMi) systems, is imperative to meet future communication requirements [1]. Up-scaling of conventional 4×4 small-scale MIMO implementations to MaMi is prohibitive in-terms of flexibility, as well as area and power cost. This work discloses a 1.1mm2 128×8 MaMi baseband chip, achieving up to 12dB array and 2× spatial multiplexing gains.
Measuring MIMO-SAR is an important part of mobile handset evaluation, following the introduction of uplink MIMO transmission schemes in LTE-Advanced. However, the measurement of MIMO-SAR is complex and time-consuming. In this paper, 6 unique dual-antenna mobile handsets, including both typical and novel designs, are analyzed to determine the dependence of MIMO-SAR on antenna configuration and corr
This paper presents a study on iconic programming support for mainly position-based lead-through programming of an ABB YuMi collaborative robot. A prototype tool supporting a hybrid programming and execution mode was developed and evaluated with 21 non-expert users with varying programming and robotics experience. We also present a comparison of the programming times for an expert robot programmer
Path loss models are the most fundamental part of wireless propagation channel models. Path loss is typically modelled as a (single-slope or multi-slope) power-law dependency on distance plus a log-normally distributed shadowing attenuation. Determination of the parameters of this model is usually done by fitting the model to results from measurements or ray tracing. The authors show that the typi
We have previously presented Intent, a medium access control scheme for WLANs based on cooperative, distributed, non-binding frame scheduling. The main idea behind Intent is intention sharing - a mechanism that allows a node to be aware of transmissions previously scheduled by its neighbors. We now extend this scheme to networks with hidden nodes. We give a formulation of the scheduling problem an
When implementing a language by means of attribute grammars, it is often useful to study example programs and their attributed trees, to understand the compiler structure, or for debugging. DrAST is a tool that allows interactive inspection of attributed trees. It is interfaced to the JastAdd metacompiler, and supports all JastAdd attribution mechanisms, such as demand evaluation, reference attrib
We present a general purpose algorithm for finding low-weight codewords as well as for decoding a received codeword in any quasi-cyclic code whose length and dimension is a multiple of a power of 2. In this paper, we apply the algorithm on a McEliece variant recently proposed by Misoczki et al. (MDPC-McEliece: New McEliece variants from moderate density parity-check codes, 2013). In their paper, t
Deciding the optimal project scope that fulfills the needs of the most important stakeholders is challenging due to a plethora of aspects that may impact decisions. Large companies that operate in rapidly changing environments experience frequently changing customer needs which force decision makers to continuously adjust the scope of their projects. Change intensity is further fueled by fierce ma
A wide band fractional-N digital PLL which uses a high resolution 2-dimension gated-Vernier time-to-digital converter (TDC) with 5.2 ps resolution is presented. The quantization noise shaping of the TDC greatly improves the in-band phase noise. While, in the same time, the 2-dimension structure makes the digital PLL (DPLL) be able to process large phase errors almost without the influence of laten
In this work we implement features for IEEE 802.11ac in the NS-3 simulator, in particular wider channels and bit-error calculations for higher modulation coding schemes. We also implement four wireless LAN deployment scenarios from the 802.11ax working group scenario document, and evaluate their performance under different operating conditions. Our simulation results demonstrate that many nodes in
Block diagram languages are often used for physical modeling and automation, where end users are domain engineers that instantiate block types and wire them together. Abstraction mechanisms in these languages allow specialists to build advanced reusable domain-specific libraries. However, this brings a tension between supporting reusability and making the language simple to comprehend for domain e
Ensuring that communication is secure, including the ability to encrypt sensitive traffic, has always been a fundamental pillar of the telecom industry. Users expect their right to privacy to be respected, and operators expect to be able to protect themselves and their customers from various kinds of attacks. But the world is changing. Encryption technologies are advancing, regulations are changin
