3.3. Methodology and organization 55
In the context of jointlocalizationandcommunication functionalities, the au- thors in  have studied a distributed antenna system providing both data commu- nication and positioning functionalities in sub-6 GHz systems. The authors assumed that the user equipments (UEs) know the positions of the BSs and attempt to esti- mate their own positions based on the received signals. Similarly, Garcia et al. in  have studied a location-aided initial access strategy for mm-Wavenetworks, in which the information of UE locations enables to speed up the channel estimation and beamforming procedures. Likewise, in , the authors investigate the resource allocation in terms of time in mm-Wave network based on localization performance bounds. The authors extend this study in  to a multi-user scenario where the trade-off between the two standalone services is studied in terms of sum-rate and PEB. Likewise, in , the authors present an iterative localization based beam selection algorithm where the transmitter, in each iteration, selects a refined finer beam based on position and orientation estimation. The refined beam again im- proves the estimation and the process continues in a virtuous loop. Extending this idea, in , the authors present the beam selection algorithm at both transmitter and receiving ends.
Abstract—In this paper we propose a belief propagation (BP) based simultaneous localizationand mapping (SLAM) approach suitable for millimeterwave (mm-Wave) networks. This approach leverages angle of arrival (AoA) and angle of departure (AoD) information with respect to multiple scatterers. Considering mea- surements from multiple base stations (BSs) and scatterers, seen as multiple sources, we solve out the data association problem from a centralized BP perspective, while jointly estimating the positions of both the mobile and scatterers. Simulations show that the proposed approach outperforms conventional distributed BS- wise BP methods in terms of estimation accuracy.
Mmwaves gives us the opportunity to use a new spectrum of band, that fall between 30 and 300 GHz . This section of the spectrum has never been used before for mobile devices and opening it up means more bandwidth for everyone, especially after having all frequency spectrum bands under 6 GHz started to get more crowded. But there is a drawback millimeterwave communications suffer from huge propagation loss compared with other communication systems in using lower carrier frequencies. Accordingly, this fact limits their range to approximately 200 m. Therefore to figure out this problem the concept of heterogeneous networks HetNETs has been introduced while densifying the macrocell
higher data rates in optical communications and next generation backhaul connectivity of Gbit/s wireless picocell base stations, ultra-high-speed optical transmission systems have been under intensive development towards the speed of 160 Gbit/s and beyond . Since the data rate depends on the carrier frequency, the most promising way is to exploit intact frequencies above 100 GHz. Alongside, THz andmillimeter-wave frequency region from 100 GHz to 10 THz has captured significant attention – for ultra-fast wireless communication links. THz techniques can find applications in many areas such as security enhancement, medical diagnosis, scientific imaging, and material identification. High-altitude THz telecommunications is being considered or a possible use for future wireless system providing data rate of more than 10 Gbit/s . Wireless expansion of the next generation broadband access fiber optic networks, Gigabit Ethernet, and multi-gigabit communication systems are very promising  which should be supported by ultra- broadband devices and circuits on both electronic and photonic sides. The possibility of minimizing the size of wireless equipment and improving the antenna directivity is other appealing features of THz andmillimeter waves, which would lead to a more compact and cost-effective system because the antenna can be integrated with other devices on the same chip. To implement the wireless system operating at such a high frequency, photonic technologies are advantageous against electronic approaches because of its inherent broadband nature, and allow us to deliver photonic THz andmillimeter-waves over long distance using optical fibers. To date, this demand has been accommodated with advanced modulation schemes and signal processing technologies at microwave frequencies. However, without increasing the carrier frequencies for more spectral resources, it may be quite difficult to keep up with the needs of users.
I. I NTRODUCTION
Recently, a huge research activity is focused on the definition and designs of future communication systems envisioned for next generation cellular networks (5G)  and wireless local and personal area networks (WLAN/WPAN) . These systems must simultaneously meet several requirements in terms of throughput, quality of service and energy saving. The usage of millimeter bands is considered essential and has proven to be an attractive solution for transmitting high data rates (Gbit/s) for short-distance applications for instance indoor environments. In this context, the 60 GHz band became a promising subject in the future for wireless broadband communication systems. At this stage, it is necessary to study the propagation at 60 GHz to obtain more knowledge about the channel characteristics at this frequency band. The propagation depends on several factors: frequency, environment, position and type of antennas used. Some studies were performed at 60 GHz in indoor static environment such as typical residential environment , and others executed in conference rooms .
Index Terms—RFID, Millimeter-Waves, Backscatter Modula- tion
I. I NTRODUCTION
Next Internet of Things (IoT) and fifth generation (5G) communication scenarios are expected to bring an increased connectivity between people and the surrounding environment, foreseeing a pervasive presence of tagged objects . Among the expected key technologies, radiofrequency identification (RFID) has attracted a great interest in the recent years. It has been adopted to overcome current bar-codes limitations in the short reading distance, with the opportunity to detect and identify batteryless tags attached to objects placed even at several meters from the reader. Current Gen. 2 ultra-high frequency (UHF)-RFID is widely exploited and studied , and new solutions have been proposed in order to enable tags localization . Recent studies have moved from UHF band to the ultrawide bandwidth (UWB) technology in the 3.1 − 10.6 GHz microwave bandwidth in order to integrate the possibility to localize tags as well as to reduce the power consumption , . In particular, the use of passive UWB- RFID solutions has a great appeal in all those applications requiring low-cost as well as good ranging performance. Since passive tags are not equipped with a transmitter, the communication relies on the modulation of the backscattered signal and several techniques were conceived in order to maximize the performance , . Unfortunately, due to power regulations constraints, it has been shown that passive UWB is strongly limited in terms of reader-tag communication range. Moreover, high accuracy localization requires multiple interrogations from at least three readers.
was made available to the community by the organizers of IEEE’s Communication Theory Workshop for an indoor positioning competition during the event . We proposed a classical learning solution, KNN, and a deep learning solution, MLP NN, to model the mapping between CSI and the location of the transmitter. Before applying the models, an essential data preprocessing step is proposed which enhances the learning process. First, the CSI complex components are studied leading to a conclusion that the magnitude component is the most stable among others. This conclusion is supported by statistical experiments and state-of-the-art works which supported our choice to use the magnitude component as the input to the learning model. This is followed by a noise and dimensionality reduction step where polynomial regression is used to fit a line through the magnitude readings. A reduced number of points is selected along the fitted line to be the input to the learning model. This preprocessing step paved the way for highly accurate position estimation using KNN and MLP NN. Our solution achieved an error 2.3 cm RMSE securing the first place in IEEE’s CTW indoor positioning competition  among 8 teams from top universities around the world such as: University of Toronto (Canada), Ruhr University Bochum (Germany), Heriot-Watt University (England), University of Padova (Italy), IMdea networks institute (Spain), Aalborg University (Denmark), and Yuan Ze University (Taiwan). During the announcement ceremony, the organizer informed Abdallah Sobehy that the estimation accuracy is better than that of the experiment authors which is an honorable testimony.
I. I NTRODUCTION
The interest inMillimeterWave Communications has been tremendously increased as a viable technology for fifth gen- eration wireless cellular systems. This is due to the fact that millimeterwave communications support the very high data rates necessary for broadband and multimedia communications thanks to the availability of large bandwidth at the high fre- quencies. However, communications at these high frequencies suffer from two main drawbacks. The first is that the millime- ter wave signal suffers from severe pathloss. To overcome this, there is an active research going on designing beamforming techniques in order to extend the signal range and enable communication between the targeted transmitter and receiver -. The second drawback is that the millimeterwave signal gets severely attenuated in the case of Non Line of Sight (NLOS) ,. To improve communications in case of NLOS, the use of intermediate relays that have LOS (or in general a better) signal with the source, the destination or among each others is suggested. Hence constructing a path between the source and destination using those relays improves the source- destination communication. In this paper, we focus on the second challenge and attempt to design a multihop relaying technique for a millimeterwavenetworks.
V. C ONCLUSION
In this paper, we considered a scenario whereby asyn- chronous D2D communication underlays an OFDMA macro- cell in the uplink. We ﬁrst demonstrated that inter-D2D in- terference is signiﬁcant for applications of D2D that result in clustered geometries. Given the suitability of new waveforms for scenarios involving asynchronous communications, we investigated a scenario in which D2D devices are capable of using either FBMC/OQAM or OFDM, in coexistence with the encompassing OFDMA macro-cell. We demonstrated that the use of FBMC/OQAM alleviates the need to develop more complex RA schemes, owing to its high spectral localizationand resulting ability to mitigate inter-D2D interference. More precisely, we showed that if D2D pairs use FBMC/OQAM, then there is no signiﬁcant performance loss incurred by performing RA and power loading without taking into account the inter-D2D interference. In that sense, FBMC/OQAM can be classiﬁed as a disruptive technology, as it allows the management of the network to be simpliﬁed through a change in the PHY layer.
Figure 5-6: Rapp model: AM/AM-conversion comparison between the Rapp model and the 3GPP HPA, input in volts, output in radian.
out-of-band radiations are introduced. Consequently, the PSD tails become higher. In this section, we study the frequency domain localization resistance to this phenomenon. In other words, the PSD of the considered waveforms after power amplification is com- pared to the CP-OFDM amplified one in order to verify if their PSD advantage is kept even after HPA. Indeed, good or excellent spectral containment will be a key parame- ter for future 5G waveform in order to support neighboring and non orthogonal signals especially after power amplification.
P. 43 2.3. MmMAGIC channel model
Millimeter–Wave Based Mobile Radio Access Network for Fifth Generation Integrated Communications (mmMAGIC) was a project co–funded by the European Commission’s 5G Public Private Partnership (PPP) program, launched in July 2015. The project participants included major infrastructure vendors (Samsung, Ericsson, Alcatel–Lucent, Huawei, Intel, and Nokia), major European operators (Orange, Telefonica), leading research institutes and universities (Fraunhofer HHI, CEA LETI, IMDEA Networks, Universities Aalto, Bristol, Chalmers and Dresden), measurement equipment vendors (Keysight Technologies, Rohde & Schwarz) and one SME (Qamcom). The project aimed at developing new concepts for mobile RAT at the mm–Wave frequency bands (6–100 GHz) for 5G. It was structured in six WPs. In WP2 led by Fraunhofer HHI, the focus was on channel measurement and modeling in the 6–100 GHz range. It should be noted that the studies carried out in this Ph.D. thesis have significantly contributed to the channel modeling work performed in the mmMAGIC project. Similarly to METIS and MiWEBA, additional channel model requirements with regards to 5G were specified. Among these requirements, there are: support of massive MIMO, support of wider frequency range, spatial consistency, continuous variation over time, etc. In mmMAGIC final deliverable , envisioned propagation environments and scenarios for mmMAGIC channel models are discussed. They include UMi street canyon and open area, indoor office, shopping mall, airport, O2I, stadium and metro station. In this variety of scenarios, more than twenty measurements campaigns were carried out across eight frequency bands between 6 and 100 GHz. Based on the acquired measurement data and some input from ray–tracing simulations also validated by measurements, a GSCM was proposed.
LoRa, Spatial filtering, Coherent combining, Angle of Arrival (AoA)
Low-power wide-area networks (LPWANs) are sought to be the networks of choice for large-scale Internet of things (IoT) communicationin urban areas. Their main selling points are a low power consumption that can span the course of a decade and a large geographical coverage of a few kilometers 1 . They also offer a cost-effective alternative to their cellular counterparts by operating on the sub-gigahertz ISM band, thus avoiding costly licenses. Unlike cellular networks which give great importance to dimensioning and have adopted industry standards concerning the quality control, privately owned LPWANs suffer from an inherent heterogeneity and poor dimensioning that hinder their performance in terms of rate, or poses serious reliability questions. This paper presents Snipe, a diversity combining LoRa system with spatial filtering techniques providing: (1) an enhanced communication range for end devices and gateways alike and (2) a precise and accurate position estimation system based on radar techniques. By exploiting the multipath effect that is omnipresent in urban andin-building settings, the Snipe gateway can increase the received signal-to-noise ratio (SNR) and hence enhance its decoding capabilities. Moreover, the system uses spatial filtering techniques in order to achieve a higher SNR at the end device. While most contributions are towards improving the uplink 2,3 , Snipe enhances both the uplink and downlink by using a Multiple-Input Multiple-Output (MIMO) design that respects the LoRa energy consumption restraints. Furthermore, MIMO support at the gateway provides low cost Angle of arrival (AoA) and end device position estimation. By offloading the position estimation processing to the gateway, the Snipe system alleviates the energy cost incurred when using GPS-enabled end devices. Moreover, by hosting the MIMO signal processing locally at the gateway, the proposed system allows combining coherently the signals from each one of the antennas elements indiscriminately. This contrasts with cloud-based approaches that involve renting compute and storage nodes as well as providing links with large bandwidth 3 .
Driven by the ever-increasing needs, radio frequency identification (RFID) has attracted much attention as evidenced by a large variety of its applications in our everyday life, ranging from security, access control, monitoring, etc…, to biomedical systems -. Typically, low RF frequencies (below 3 GHz) have been used for RFID communications and applications. The main factors impeding the evolution of RFID technology over these RF bands are the limited available bandwidth resources and the large tag size (mainly dominated by antenna size at these frequencies and by the battery if active tags are considered). However, the emerging millimeter-wave identification (MMID) technology is set out to exploit smaller antenna size and larger available bandwidths in order to alleviate these limitations , . Integrating the tag’s antenna on a single-chip (feasible at millimeter-wave frequencies thanks to smaller antenna size), wirelessly harvesting sufficient dc power from incoming millimeter-wave signals (thereby providing an energy autonomy without the need of a battery and at the same time allowing miniaturization), and transmitting data to the reader over a large bandwidth at millimeter-wave frequencies will lead to the development of a new generation of high data-rate, battery-free µRFID technology for applications that cannot be made possible today. In parallel, this MMID concept is fully compatible with upcoming and future applications of millimeter-wave technology in wireless communications such as 5G technologies and systems that are being discussed and developed worldwide.
Millimeter-wave MIMO system has been studied in previous work. The channel modeling was studied for millimeter-wave MIMO in , in which two kinds of scenario were examined to observe the consequences of the MIMO LoS channels, or more generally, sparse scattering channels that have antennas with moderate separation in both indoor and outdoor environment. The results are different from the existing lower frequency MIMO systems because some special paths are dominant for the directional millimeter-wave MIMO transmission, compared to a rich scattering environment at lower frequencies. The crosstalk of the millimeter-wave MIMO system was discussed in , and the results demonstrated that linear MIMO crosstalk was relatively benign, as a result of being corrected by the MIMO equalizers, while nonlinear crosstalk would be much more harmful to the system that was not corrected by the MIMO equalizers. In addition, it is not feasible to realize a high precision analog/digital (AD) conversion of millimeter-wave signals by using the current technologies. Therefore, it is necessary to perform most of the signal processing to separate the data signals from different transmitters in the analog section instead of in the digital section.
I. I NTRODUCTION
The number of wirelessly connected devices along with the number of users are exponentially increasing nowadays owning to, e.g., the advent of tablets and smartphones. The 5th Generation of mobile communications (5G) is expected to offer extreme broadband, pervasive and large connectivity with very low latency . The usual frequency bands for mobile communications systems (i.e., 300 MHz-6 GHz) can not provide satisfactory quality of service due to the limited band- width therein. Therefore, the World Radio-communications Conference (WRC) 2015 identified several of the millimeterwave (mmW) bands for further study for mobile applications . The use of these frequency bands will considerably increase the channel capacity due to the large available bandwidth. However, the radio channel ought to be well understood at the millimeter frequencies by the designers of future communications systems. Indeed, the knowledge of the channel state information is important in order to design efficient and optimal communications systems. The path loss models are important for predicting the received signal strength at any location in the considered environment whereas the path loss exponent gives an extent of the coverage. The delay dispersion - rms delay spread - is needed to assess the maximum achievable throughput without equalization. The space selectivity information (i.e., angular spread) of an envi- ronment is a prerequisite to achieve optimal beamforming for directive antennas elements in MIMO systems . Moreover, the angular spread provides crucial information such as the fading rate of the signal, the cross-correlation function in MIMO systems .
2 F U S C A L D O E T A L .
an original theoretical framework allowed the derivation of several physical insights on the problem. The proposed analysis revealed that the design of an efficient X-wave launcher (i.e., able to focus energy along both the trans- verse and the longitudinal axis) usually requires a moderate wavenumber dispersion, a wide fractional bandwidth, and an electrically-large aperture. These requirements actually limit the class of suitable planar devices at millimeter waves to those using holographic approaches [15, 27] and leaky-wave techniques [26, 28]. In those works, the design process takes advantage of the concept of metric of con- finement introduced in . The design criteria adopted in [15, 28] will be clearly outlined in this manuscript.
By Henk Wymeersch, Member IEEE , Jaime Lien, Member IEEE , a n d M o e Z . W i n , Fellow IEEE
ABSTRACT | Location-aware technologies will revolutionize many aspects of commercial, public service, and military sectors, and are expected to spawn numerous unforeseen applications. A new era of highly accurate ubiquitous location- awareness is on the horizon, enabled by a paradigm of cooperation between nodes. In this paper, we give an overview of cooperative localization approaches and apply them to ultrawide bandwidth (UWB) wireless networks. UWB transmis- sion technology is particularly attractive for short- to medium- range localization, especially in GPS-denied environments: wide transmission bandwidths enable robust communicationin dense multipath scenarios, and the ability to resolve subnanosecond delays results in centimeter-level distance resolution. We will describe several cooperative localization algorithms and quantify their performance, based on realistic UWB ranging models developed through an extensive mea- surement campaign using FCC-compliant UWB radios. We will also present a powerful localization algorithm by mapping a graphical model for statistical inference onto the network topology, which results in a net-factor graph, and by develop- ing a suitable net-message passing schedule. The resulting algorithm (SPAWN) is fully distributed, can cope with a wide variety of scenarios, and requires little communication over- head to achieve accurate and robust localization.
In order to validate our technological approach a lot of passive components were designed, fabricated and manufactured in our laboratory -. A thickness of 125 µm was selected for the Kapton film as a best trade-off between: (i) the commercially available thickness of Kapton films, (ii) the electromagnetic performances required by typical antennas (e.g. patch antennas) that can be used for millimeterwave applications, (iii) the mechanical properties. Fig. 3 shows a 4 inch kapton wafer including: (i) circular ring resonators (CRR), (ii) cross dipole antennas (by using strip or slot based topologies), (iii) patch antennas, (iv) rectennas (an acronym from rectifier antenna). CRR are useful structures for the characterization of Kapton dielectric properties (measurement of the relative electric permittivity ε r and dielectric loss