Indoor location systems based on ultra-wideband (UWB) technology have become very popular in recent years following the introduction of a number low-cost devices market capable providing accurate distance measurements. Although promising, UWB also suffer from classic problems found when working indoor scenarios, especially there is no clear line-of-sight (LOS) between emitter and receiver, causing estimation error to increase up several meters. In this work, machine learning (ML) techniques...

Today's needs for monitoring and control of different devices in organizations require an Internet Things (IoT) platform that can integrate heterogeneous elements provided by multiple vendors using protocols, data formats communication technologies. This article provides a comprehensive review all the architectures, technologies, protocols most commonly used existing IoT platforms. On this basis, comparative analysis widely open source platforms is presented. exhaustive comparison based on...

Diversity occurs whenever several copies of the same transmitted signal arrive at a receiver. Such situation allows for improving performance wireless communication system transmitting over radio channel without increasing transmit power. Previous works have shown that time-modulated arrays are capable faithfully acquiring digital signals while exploiting angular diversity through adaptive beamforming their harmonic patterns. In this work, we take step further and consider employing linear...

In the world of Internet Things (IoT), obtaining physical location devices has always been a task great interest for developing increasingly complex location-based services (LBS). That is why in recent years wireless communication standards have incorporating new additions focused on providing localization mechanisms to technologies widely used IoT world, such as Wi-Fi or Bluetooth. particular, IEEE 802.11-2016 standard introduced ranging estimation between two through so-called fine time...

This article discusses the development of an IoT system for monitoring and controlling various devices systems from different vendors. The authors considered key challenges in projects, such as interoperability integration, scalability, data storage, processing, visualization, during design deployment phases. In addition to these general challenges, also delve into specific integration they encountered. Various were integrated five real-world scenarios a university campus environment are...

One of the primary features time-modulated arrays (TMAs) is their ability to adapt harmonic patterns exploit angular diversity multipath wireless channels. In such a case, TMA excitations must provide an adequate level windowing in order safeguard both antenna efficiency and signal-to-noise ratio at reception. this work, we propose time-modulate array with periodic sum-of-weighted-cosine (SWC) pulses rather than rectangular corresponding on-off switches conventional TMAs. We show that how...

Bipolar (±1) sequences with no zero state suit particularly well for safeguarding the switched feeding network efficiency when applied to time-modulated arrays. During of a conventional time-modulating sequence, if given array element is off, certain amount energy transmitted/received signal wasted. We propose novel single sideband phased (TMPA) architecture governed by realistic bipolar squared in which rise/fall time switches considered. By using single-pole dual-throw and...

Wireless communications are widely based on linear digital modulation methods, which introduce the baseband information in amplitude and/or phase of a carrier sinusoid. Time-modulated arrays, other hand, constitute an interesting technique capable adapting power radiation pattern antenna array. In this work, we study from theoretical point view impact time-modulated arrays transmission linearly modulated communication signals. The work focuses requirements to safeguard integrity signal and...

Location and tracking needs are becoming more prominent in industrial environments nowadays. Process optimization, traceability or safety some of the topics where a positioning system can operate to improve increase productivity factory warehouse. Among different options, solutions based on ultra-wideband (UWB) have emerged during recent years as good choice obtain highly accurate estimations indoor scenarios. However, typical harsh wireless channel conditions found inside environments,...

Hardware platforms and testbeds are an essential tool to evaluate, in realistic scenarios, the performance of wireless communications systems. In this work we present a multiuser Multiple-Input Multiple-Output (MIMO) testbed made up 6 nodes, each one with 4 antennas, which allows us evaluate Interference Alignment (IA) techniques indoor scenarios. We specifically study IA for 3-user interference channel 5GHz band. Our analysis identifies main practical issues that potentially degrade such as...

We present a single sideband time-modulated multibeam phased array governed by periodic Nyquist pulsed signals. A pulse is physically realizable approach to the ideal sinc function. Hence, its low-pass spectrum suits particularly well for arrays (TMAs) perform harmonic beam steering. Contrarily switched TMAs and standard solutions based on variable phase shifters, performance complexity of proposed time modulation scheme rather robust when increasing number multibeams.

Ultra-wideband (UWB) devices have been largely considered for indoor location systems due to their high accuracy. However, as in other wireless systems, such accuracy is significantly degraded under non-line-of-sight (NLOS) propagation conditions. Therefore, the identification of NLOS conditions essential mitigate inaccuracies propagation. Nonetheless, most techniques identify situations are based on study channel impulse response (CIR), which not practical and even becomes unfeasible when...

The rapid evolution of nowadays wireless communication systems constitutes a challenge for the versatile and flexible evaluation transmissions under different scenarios. In order to evaluate current fourth generation (4G) future fifth (5G) techniques, modular link-level simulator was developed at GTEC group University A Coruña. this paper, structure as well how use it are presented in detail. allows performing link layer simulations both Orthogonal Frequency-Division Multiplexing (OFDM)...

Conventional time-modulated arrays are based on the application of variable-width periodical rectangular pulses (easily implemented with radio frequency switches) to individual antenna excitations. However, a serious bottleneck arises when number exploited harmonic beams increases. In this context, modest windowing features produce an inflexible and ineffective beamforming. The use other pulses, such as sum weighted cosines, partially solves these issues at expense introducing additional...

Multimedia and data-based services experienced a nonstopping growth over the last few years. People are continuously on move using devices to access multimedia contents or other services. Due this, railway companies showing great interest in deploying broadband mobile wireless networks high-speed-trains with aim of supporting both passenger provisioning as well automatic train control signaling. Nowadays, most widely used technology for communications between trains infrastructure is GSM...

Indoor positioning systems based on radio frequency inherently present multipath-related phenomena. This causes ranging such as ultra-wideband (UWB) to lose accuracy when detecting secondary propagation paths between two devices. If a algorithm uses measurements without considering these phenomena, it will face critical errors in estimating the position. work analyzes performance obtained localization system combining location algorithms with machine learning techniques applied previous...

ultra-wideband (UWB) technology enables centimeter-level localization systems based on the accurate estimation of actual distance between transmitter and receiver, by means precise signal time-of-flight. However, this is only possible when correctly detecting first path incoming instead a bounce or reflection, which becomes challenging in non line-of-sight (NLOS) situations. There are many different approaches literature to alleviate wrong detection UWB path. One them considers machine...

Time-modulated arrays (TMAs) can effectively perform beamsteering over the first positive harmonic pattern by applying progressively delayed versions of stair-step approximations a sine waveform to antenna excitations. In this letter, we consider synthesizing such means Haar wavelets. functions constitute complete orthonormal set rectangular waveforms, which have ability represent given function with high degree accuracy using few constituent terms. Hence, when they are applied TMA...

Long Term Evolution (LTE) is expected to substitute the Global System for Mobile Communications (GSM) as radio access technology railway communications. Recently, especial attention has been devoted high-speed trains since this particular environment poses challenging problems in terms of performance simulation and measurement. In order severely decrease cost complexity measurement campaigns, we have proposed a technique induce effects caused by highly-time varying channels on Orthogonal...

Long-Term Evolution (LTE) is expected to substitute the Global System for Mobile (GSM) Communications as radio access technology railway communications. Recently, considerable attention has been devoted high-speed trains since this particular environment poses challenging problems in terms of performance simulation and measurement. In order considerably decrease cost complexity measurement campaigns, we have proposed a technique induce effects caused by highly time-varying channels on...

The design of efficient time-modulated arrays (TMAs) for multi-beam steering purposes must be based on both a type periodical sequences that guarantees an adequate windowing exploited harmonics, and feeding network capable providing low hardware insertion losses. Compliance with these two requirements is not simple aggravated by the fact that, as number harmonic beams increases, only drastically decreases antenna efficiency, but also beam flexibility. In this work, we propose three different...

Recently, analog joint source-channel coding has been proposed as a means of achieving near-optimum performance for high data rates with very low complexity. However, no experimental evaluation showing the practical feasibility this scheme performed to date. In paper, we describe software-defined radio implementation an coded wireless transmission system. Experimental carried out in indoor environment making use testbed show that perfectly matches originally reported by simulations additive...