Test of 5G multicarrier schemes using Software Defined Radio

5G aims to be a revolutionary jump in terms of data rates, diminished latency, massive connectivity, the Internet of Things and so on. Right now, multicarrier modulation schemes are widely used because of their great advantages. One particularly famous modulation scheme is Orthogonal Frequency Division Multiplexing (OFDM), which is one of the most adopted technique in the world. We know that wireless channels are frequency selective, meaning that the frequency response of the channel varies according to the variation of the frequency with a sinusoidal behaviour. By dividing the available bandwidth into smaller bandwidths, we can approximate the channel as flat in each one of them. Moreover, we can also take advantage of the property of orthogonality between the subcarriers. The most famous architectures that use OFDM are WiFi and Long-Term Evolution (LTE) networks. For 5G networks, other modulation schemes are taken in consideration. This is because even if OFDM has lots of advantages, it suffers in particular from a considerable loss of power due to the utilization of Cyclic Prefix (CP), which avoids Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI), but also from a very high Peak to Average Power Ratio (PAPR). one of the main goals is to find an alternative solution to this problem to reach a lower PAPR, such as Filter Bank Multicarrier (FBMC) and Universal Filter Multicarrier (UFMC). FBMC doesn’t use any CP. What it does is an operation of filtering before the input to the (Inverse Fast Fourier Transform) IFFT, in general an Inverse Discrete Fourier Transform (IDFT) block. There are two main versions of FMBC: Staggered Multitone (SMT) and Cosine-modulated Multitone (CMT). The one which is taken in consideration in this elaborate is the SMT. SMT uses an Offset Quadrature Amplitude Modulation (OQAM) in which the quadrature component (the imaginary part) of the signal is sent with a delay of half the symbol duration. UFMC, on the other hand, slices each subcarrier into smaller subbands and performs operations of filtering (more specifically a Dolph-Chebyshev filter is uesd) and IFFT on each of them. Thanks to these strategies we can reach a lower PAPR and other advantages. In this elaborate an implementation of the transmitter schemes of OFDM, FBMC and UFMC will be illustrated by the software enviroment development LabVIEW. Furthermore, with the utilization of the NI-USRP, a Software Defined Radio (SDR) by National Instrument, which is the same provider of LabVIEW, and also with the help of a spectrometer, it has been possible to run a simulation and transmit the three waveform in the Telecommunications Laboratory situated in the "Universidad Carlos III de Madrid", the host university which I attended during my Erasmus stay in the city of Madrid, Spain. The purpose was, after having learned how to work with LabVIEW and USRP, to go deeper to the topic of Multicarrier Systems, have a knowledge about 5G Mobile Networks and study the modulation schemes aforementioned, to implement their transmitter and receiver schemes and eventually to simulate the transmission of the waveforms and collect results such as the PAPR, the Power and the Bandwidth in order to validate the work I've done. My task was a part of a project which provides the connection between transmitter and receiver of the different modulation schemes by using two USRP.