A 2x2 MIMO DVB-T2 System: Design, New Channel Estimation Scheme and Measurements With Polarization Diversity

The increasing interest in MIMO (Multiple-Input Multiple-Output) systems has given rise to a prolific research activity in recent years. Both theoretical and practical issues have been studied. However, so far few MIMO testbeds or prototypes have been built for DVB-T or future standards. In this paper, a novel 2 × 2 MIMO testbed specifically designed for evaluating the performances of a DVB-T2 MIMO system is presented. The description of signal processing is detailed including a new scheme to estimate the MIMO channel matrix. Finally, measurement results with different polarization schemes are presented for typical scenarios, obtaining higher capacity in LoS situations using polarization diversity

Deploying an NFV-Based Experimentation Scenario for 5G Solutions in Underserved Areas

Presently, a significant part of the world population does not have Internet access. The fifth-generation cellular network technology evolution (5G) is focused on reducing latency, increasing the available bandwidth, and enhancing network performance. However, researchers and companies have not invested enough effort into the deployment of the Internet in remote/rural/undeveloped areas for different techno-economic reasons. This article presents the result of a collaboration between Brazil and the European Union, introducing the steps designed to create a fully operational experimentation scenario with the main purpose of integrating the different achievements of the H2020 5G-RANGE project so that they can be trialed together into a 5G networking use case. The scenario encompasses (i) a novel radio access network that targets a bandwidth of 100 Mb/s in a cell radius of 50 km, and (ii) a network of Small Unmanned Aerial Vehicles (SUAV). This set of SUAVs is NFV-enabled, on top of which Virtual Network Functions (VNF) can be automatically deployed to support occasional network communications beyond the boundaries of the 5G-RANGE radio cells. The whole deployment implies the use of a virtual private overlay network enabling the preliminary validation of the scenario components from their respective remote locations, and simplifying their subsequent integration into a single local demonstrator, the configuration of the required GRE/IPSec tunnels, the integration of the new 5G-RANGE physical, MAC and network layer components and the overall validation with voice and data services

An FPGA implementation of OFDM transceiver for LTE applications

The paper presents a real-time transceiver using an Orthogonal Frequency-Division Multiplexing (OFDM) signaling scheme. The transceiver is implemented on a Field- Programmable Gate Array (FPGA) through Xilinx System Generator for DSP and includes all the blocks needed for the transmission path of OFDM. The transmitter frame can be reconfigured for different pilot and data schemes. In the receiver, time-domain synchronization is achieved thr ough a joint maximum likelihood (ML) symbol arrival-time and carrier frequency offset (CFO) estimator through the redundant information contained in the cyclic prefix (CP). A least-squares channel estimation retrieves the channel state information and a simple zero-forcing scheme has been implemented for channel equalization. Results show that a rough implementation of the signal path can be impleme nted by using only Xilinx System Generator for DSP

Robotic Wireless Sensor Networks

In this chapter, we present a literature survey of an emerging, cutting-edge, and multi-disciplinary field of research at the intersection of Robotics and Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system that aims to achieve certain sensing goals while meeting and maintaining certain communication performance requirements, through cooperative control, learning and adaptation. While both of the component areas, i.e., Robotics and WSN, are very well-known and well-explored, there exist a whole set of new opportunities and research directions at the intersection of these two fields which are relatively or even completely unexplored. One such example would be the use of a set of robotic routers to set up a temporary communication path between a sender and a receiver that uses the controlled mobility to the advantage of packet routing. We find that there exist only a limited number of articles to be directly categorized as RWSN related works whereas there exist a range of articles in the robotics and the WSN literature that are also relevant to this new field of research. To connect the dots, we first identify the core problems and research trends related to RWSN such as connectivity, localization, routing, and robust flow of information. Next, we classify the existing research on RWSN as well as the relevant state-of-the-arts from robotics and WSN community according to the problems and trends identified in the first step. Lastly, we analyze what is missing in the existing literature, and identify topics that require more research attention in the future