arXiv subjects

Pol Henarejos

Publications and source records attributed to Pol Henarejos.

30 records · Page 2Linked to original sources

arXiv2018

Advanced Signal Processing Techniques for Fixed and Mobile Satellite Communications

Enabling ultra fast systems has been widely investigated during recent decades. Although polarization has been deployed from the beginning in satellite communications, nowadays it is being exploited to increase the throughput of satellite links. More precisely, the application of diversity techniques to the polarization domain may provide reliable, robust, and fast satellite communications. Better and more flexible spectrum use is also possible if transmission and reception can take place simultaneously in close or even overlapping frequency bands. In this paper we investigate novel signal processing techniques to increase the throughput of satellite communications in fixed and mobile scenarios. First, we investigate four-dimensional (4D) constellations for the forward link. Second, we focus on the mobile scenario and introduce an adaptive algorithm which selects the optimal tuple of modulation order, coding rate, and MIMO scheme that maximizes the throughput constraint to a maximum packet error rate. Finally, we describe the operation of radio transceivers which cancel actively the self-interference posed by the transmit signal when operating in full-duplex mode.

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arXiv2018

An SDR Implementation of a Visible Light Communication System Based on the IEEE 802.15.7 Standard

The aim of this paper is to present an implementation of a functional IEEE 802.15.7 real-time testbed based on the Software Defined Radio (SDR) concept. This implementation is built with low cost commercial off-the-shelf (COTS) analog devices and the use of Universal Software Radio Peripheral version 2 (USRP2) equipment combined with a generic object-oriented framework that takes advantage of several open source software libraries. The prototype is validated in a controlled laboratory environment with an over-the-air measurement campaign.

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arXiv2018

Prototyping with SDR: a quick way to play with next-gen communications systems

In this paper we present our approach regarding the implementation of new wireless radio receiver exploiting filterbank techniques, using a software-development driven approach. Since most of the common radio communications systems share a similar structure, this can be exploited creating a framework which provides a generic layout and tools to construct a reconfigurable transmitter and/or receiver. By combining the use of the Universal Software Radio Peripheral version 2 (USRP2) with a generic object-oriented framework of our own built on top of the GNU Radio software framework, we have been able to quickly implement a working proof of concept of an Uplink (UL) Filterbank Multicarrier (FBMC) receiver, both for SingleInput Single-Output (SISO) and Multiple-Input Multiple-Output (MIMO) scenario, within the project of the 7th European framework called PHYDYAS. We described here the methodology we have applied from software engineering in order to build this demonstrator, which shows the suitability of using Software Defined Radio (SDR) technologies for fast prototyping of new wireless communication systems.

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arXiv2018

Pushing for higher rates and efficiency in Satcom: the different perspectives within SatNExIV

SatNEx IV project aims at studying medium and long term directions of satellite telecommunication systems for any of the commercial or institutional applications that can be considered appealing by key players although still not mature enough for attracting industry or initiating dedicated ESA R&D activities. This paper summarizes the first year activities identified as very promising techniques for next generation satellite communication systems. Concretely, very high throughput satellite trunking, physical layer advances for full-duplex and multipolarization systems, network coding applications and multiple access schemes for information centric networking are briefly presented. For all the activities, we identify the scenarios under study so as the preliminary technical solutions to be further investigated.

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arXiv2018

NOMA Assisted Joint Broadcast and Multicast Transmission in 5G Networks

In this paper, we employ the non-orthogonal multiple access (NOMA) technique to convey joint broadcast and multicast streams to a set of users. Thanks to the spatial beamforming, different groups of users is able to receive different streams in addition to the common broadcast information. With the proposed scheme, the same time-frequency resources can be shared between different streams, without requiring additional bandwidth. The transmitter implementation is presented and two receiver classes are considered based on Successive Interference Cancellation (SIC) and Joint Decoding (JD) approaches. In addition to the performance assessment via simulation, a real hardware proof of concept implementation of the proposed technique is performed in order to show the practical viability of the proposed scheme.

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arXiv2018

Rapid Prototyping of Standard-Compliant Visible Light Communications System

This article describes the implementation of a prototype visible light communications system based on the IEEE 802.15.7 standard using low-cost commercial off-the-shelf analog devices. The aim of this article is to show that this standard provides a framework that could promote the introduction of applications into the market. Thus, these specifications could be further developed, reducing the gap between the industry and research communities. The implemented prototype makes use of software defined radio platforms to interface between the analog devices and the computer where the signal processing is performed. The use of this concept provides the system with enough flexibility and modularity to include new features in the prototype without requiring long development time.

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arXiv2018

The CTTC 5G end-to-end experimental platform: Integrating heterogeneous wireless/optical networks, distributed cloud, and IoT devices

The Internet of Things (IoT) will facilitate a wide variety of applications in different domains, such as smart cities, smart grids, industrial automation (Industry 4.0), smart driving, assistance of the elderly, and home automation. Billions of heterogeneous smart devices with different application requirements will be connected to the networks and will generate huge aggregated volumes of data that will be processed in distributed cloud infrastructures. On the other hand, there is also a general trend to deploy functions as software (SW) instances in cloud infrastructures [e.g., network function virtualization (NFV) or mobile edge computing (MEC)]. Thus, the next generation of mobile networks, the fifth-generation (5G), will need not only to develop new radio interfaces or waveforms to cope with the expected traffic growth but also to integrate heterogeneous networks from end to end (E2E) with distributed cloud resources to deliver E2E IoT and mobile services. This article presents the E2E 5G platform that is being developed by the Centre Tecnològic de Telecomunicacions de Catalunya (CTTC), the first known platform capable of reproducing such an ambitious scenario.

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arXiv2018

Dual Polarized Modulation and Receivers for Mobile Communications in Urban Areas

Achieving an increase in the spectral efficiency (SE) has always been a major driver in the design of communication systems. The use of MIMO techniques in mobile communications has achieved significant benefits in improving the system throughput. The basic underlying concept of MIMO is to exploit the signal and channel characteristics to eliminate interference between multiple transmissions. Departing from the work carried out under the industrial projects \cite{NGW,Henarejos}, we extend the results provided in their respective reports. The goal is to increase the SE without an increment of radiated energy without any Channel State Information at Transmitter (CSIT) and feedback at the transmitter and maintaining a very low computational complexity at the receiver. Although a priori additional power is required to increase the SE, we demonstrate that the proposed Polarized Modulation (PMod) scheme exploits the polarization diversity reducing the required EbN0 and adding an extra bit. We also introduce two receivers to demodulate this scheme of different computational complexities. We describe a Near Optimal Detector (NOD) which achieves almost the same performance as the optimal detector based on the Maximum Likelihood Detection (MLD), but with lower computational complexity. Finally, the results demonstrate that the PMod requires less EbN0 compared with the single polarization case, guarantees the robustness in the presence of the cross-polarization and validates that PMod can multiplex two streams of different Quality of Service (QoS).

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arXiv2018

Dual Polarized Modulation and Reception for Next Generation Mobile Satellite Communications

This paper presents the novel application of Polarized Modulation (PMod) for increasing the throughput in mobile satellite transmissions. One of the major drawbacks in mobile satellite communications is the fact that the power budget is often restrictive, making unaffordable to improve the spectral efficiency without an increment of transmitted power. By using dual polarized antennas in the transmitter and receiver, the PMod technique achieves an improvement in throughput of up to $100$\% with respect to existing deployments, with an increase of less than $1$ dB at low \ebn regime. Additionally, the proposed scheme implies minimum hardware modifications with respect to the existing dual polarized systems and does not require additional channel state information at the transmitter; thus it can be used in current deployments. Demodulation (i.e. detection and decoding) alternatives, with different processing complexity and performance, are studied. The results are validated in a typical mobile interactive scenario, the newest version of TS 102 744 standard (Broadband Global Area Network (BGAN)), which aims to provide interactive mobile satellite communications.

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arXiv2018

Capacity Analysis of Index Modulations over Spatial, Polarization and Frequency Dimensions

Determining the capacity of a modulation scheme is a fundamental topic of interest. Index Modulations (IM), such as Spatial Modulation (SMod), Polarized Modulation (PMod) or Frequency Index Modulation (FMod), are widely studied in the literature. However, finding a closed-form analytical expression for their capacity still remains an open topic. In this paper, we formulate closed-form expressions for the instantaneous capacity of IM, together with its $2$nd and $4$th order approximations. We show that, in average, the $2$nd approximation error tends to zero for low Signal to Noise Ratio (SNR) and is $o\left(\textrm{SNR}\right)$. Also, a detailed analysis of the ergodic capacity over Rayleigh, Rice and Nakagami-$m$ channel distributions is provided. As application of the capacity analysis, we leverage the proposed expressions to compute the ergodic capacities of SMod for different antenna configuration and correlations, PMod for different channel components and conditions, and FMod for different frequency separations.

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arXiv2018

Forward Link Interference Mitigation in Mobile Interactive Satellite Systems

We present the results of the performance evaluation of polarization-time coding and soft interference cancellation in multi-beam satellite systems affected by co-channel interference in realistic setups. The standard of Broadband Global Area Network service (BGAN) has been considered as reference for the physical layer and realistic interference and channel models have been adopted. The work has been carried out in the framework of the Next Generation Waveform for Increased Spectral Efficiency (NGWISE) project founded by the European Space Agency (ESA).

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arXiv2018

End-to-end 5G services via an SDN/NFV-based multi-tenant network and cloud testbed

5G has a main requirement of highly flexible, ultralow latency and ultra-high bandwidth virtualized infrastructure in order to deliver end-to-end services. This requirement can be met by efficiently integrating all network segments (radio access, aggregation and core) with heterogeneous wireless and optical technologies (5G, mmWave, LTE/LTE-A, Wi-Fi, Ethernet, MPLS, WDM, software-defined optical transmission, etc.), and massive computing and storage cloud services (offered in edge/core data centers). This paper introduces the preliminary architecture aiming at integrating three consolidated and standalone experimental infrastructures at CTTC, in order to deploy the required end-to-end top-to-bottom converged infrastructure pointed out above for testing and developing advanced 5G services.

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