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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

In this paper, we study random puncturing of protograph-based spatially coupled low-density parity-check (SC- LDPC) code ensembles. We show that, with respect to iterative decoding threshold, the strength and suitability of an LDPC code ensemble for random puncturing over the binary erasure channel (BEC) is completely determined by a single constant that depends only on the rate and iterative deco

This work focuses on the design of SC-LDPC codes for transmission over non-ergodic, block-fading channels. Our main contribution is an algorithm, allowing to start from a (J,K )-regular, uncoupled LDPC ensemble, from which one can recursively build up a protograph-based SC-LDPC ensemble having any target diversity order d. The diversity order is achieved assuming a low-complexity iterative decodin

Background: There is a need for ecient regression testing in most software development organizations. Often the proposed solutions involve automation. However, despite this being a well researched area, research results are rarely applied in industrial practice. Aim: In this paper we aim to bridge the gap between research and practice by providing examples of how evidence-based regression testing

In this work we present a new low-power medium access scheme for sensor-type networks specifically with low traffic intensity. We call the proposed scheme DCW-MAC where ultra-low-power wake-up receivers are combined with optimal duty-cycled listening. First we introduce a framework for the analysis of energy consumption of the studied network type, then we use it to optimize the MAC scheme to achi

Requirements Engineering and Testing are considered inseparable and together enable successful projects. One could make a statement that serious negligence of any of the two will bring catastrophic consequences for the project, delays, failures and unhappy customers. Thus, alignment and cooperation between the two are not only recommended but highly required for contemporary complex software and s

Analog decoders are constructed based on interconnecting CMOS Gilbert vector multipliers using transistors operating in the sub-VT region. They are seen as an interesting alternative to digital implementations with a low transistor count and a potential for a very low power consumption. Analog implementation makes the circuit sensitive to mismatch, requiring careful transistor sizing. A simulation

In this paper we prove threshold saturation for spatially coupled turbo codes (SC-TCs) and braided convolutional codes (BCCs) over the binary erasure channel. We introduce a compact graph representation for the ensembles of SC-TC and BCC codes which simplifies their description and the analysis of the message passing decoding. We demonstrate that by few assumptions in the ensembles of these codes,

Signal-to-noise ratio (SNR) estimation is commonly used in wireless receivers to enhance the performance in different ways. In this paper a novel low complexity SNR estimator for OFDM is proposed. The estimator might be implemented using floating point representation or by using only the sign-bit, and can if desired be effectively implemented by reconfiguring the standard correlator used for time-

In the emerging Delay Tolerant Networks (DTNs) content dissemination platform, mobile nodes opportunistically exchange content as they meet, with the intent of sharing content among nodes with common interests. During a meeting, nodes can exchange both content of direct interest to themselves as well as content that is of interest to a larger set of nodes that may be encountered in the future. The

Reference attribute grammars (RAGs) can be used to express semantics as super-imposed graphs on top of abstract syntax trees (ASTs). A RAG-based AST can be used as the in-memory model providing semantic information for software language tools such as compilers, refactoring tools, and meta- modeling tools. RAG performance is based on dynamic attribute evaluation with caching. Caching all attributes

Many large companies, from the traditionally proprietary software industry, are opening up and embracing the open source software (OSS) development process model as a part of their business strategy. Despite the recognized potential the OSS community offers, there are still many questions and unknowns about the transition process. We present an extensive analysis of static software quality metric

Numerous geometric problems in computer vision in- volve the solution of systems of polynomial equations. This is true for problems with minimal information, but also for finding stationary points for overdetermined problems. The state-of-the-art is based on the use of numerical linear algebra on the large but sparse co- efficient matrix that represents the expanded original equation set. In this

IoT networks are getting overcrowded following the vast increase in number of Internet-of-Things (IoT) devices and connections. Networks can be extended with more gateways, increasing the number of supported devices. However, as investigated in this work, massive MIMO has the potential to increase the number of simultaneous connections and moreover lower the energy expenditure of these devices. We

Open Government Data (OGD) is an important driver for open innovation among public entities. However, extant research highlights a need for improved feedback loops, collaboration, and a more demand-driven publication of OGD. In this study, we explore how public platform providers can address this issue by enabling collaboration within OGD ecosystems, both in terms of the OGD, and any related Open

In the recent Internet-of-Things (IoT) era where biomedical applications require continuous monitoring of relevant data, edge computing keeps gaining more and more importance. These new architectures for edge computing include multi-core and parallel computing capabilities that can enable prevention diagnosis and treatment of diseases in ambulatory or home-based setups. In this article, we explore