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Under high-mobility scenarios, the traditional coherent demodulation schemes (CDS) have limited performance, because reference signals cannot effectively track the channel variations with an affordable overhead. As an alternative solution, non-coherent demodulation schemes (NCDS) based on differential modulation have been proposed. Even in the absence of reference signals, they are capable of outperforming the CDS with a reduced complexity. The literature on NCDS laid the theoretical foundations for simplified channel and signal models, often single-carrier and spatially uncorrelated flat-fading channels. This chapter explains the most recent results assuming orthogonal frequency division multiplexing (OFDM) signaling and realistic channel models.

Proceeding of: IEEE Global Communications Conference (GLOBECOM 2022) A novel time division duplex massive MIMO approach based on performing a blind channel estimation in the uplink using differentially encoded data and a precoding in the downlink, also with differentially encoded data, is proposed. In this system, the use of any type of explicit pilot symbol is completely avoided while maintaining spatial multiplexing capabilities in the downlink. We perform an analysis of the full system in terms or signal-to-interference-and-noise ratio (SINR) for the uplink and the downlink. The performance of the channel estimation using differentially encoded data is also analyzed, since it affects the performance of the downlink data transmission. A multi-user allocation strategy in an OFDM grid is proposed. The analysis is corroborated via numerical results and the proposed scheme is shown to outperform its coherent counterpart. This work has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie ETN TeamUp5G, grant agreement No. 813391, and the Spanish National Project IRENE-EARTH (PID2020-115323RB-C33) (MINECO/AEI/FEDER, UE).

Proceedings of IEEE GLOBECOM 2022: IEEE Global Communications Conference, 4-8 December 2022, Rio de Janeiro, Brazil. The Reconfigurable Intelligent Surfaces (RIS) constitute one of the prominent technologies for the next generation of wireless communications. They are mainly envisioned to efficiently enhance the signal coverage in cases where the direct communication link is weak or obstructed. Recently, beam training based on codebook selection has been proposed as a low-latency means for tuning the RIS phase profile according to a desired performance metric. However, it requires the transmission of reference signals to measure the performance with different RIS phase configurations available in the codebook, which reduces the spectral efficiency. In this paper, we consider the uplink of a Multiple-Input Signal-Output (MISO) communication system with Orthogonal Frequency-Division Multiplexing (OFDM) and present a novel scheme for simultaneous RIS phase configuration and data transmission. The proposed scheme is based on non-coherent differential modulation, which is deployed both in the beam training and the data transmission phases. In the former phase, it also enables energy measurement for the determination of the best RIS phase profile. Then, in the latter phase, a higher throughput can be established through the high gain reflective link. Our numerical results showcase that our proposal can double the system throughput with lower complexity, as compared to the generic state-of-the-art approach. This work has been funded by the Spanish National project IRENE-EARTH (PID2020-115323RB-C33/AEI /10.13039/501100011033) and the EU H2020 RISE-6G project under grant number 101017011.

Proceeding of: 31st Annual Conference of the European Association for Education in Electrical and Information Engineering (EAEEIE 2022), Coimbra, Portugal, 26 June-1 July 2022 Many of the new mobile communication devices will be things that power and monitor our homes, city infrastructure and transport. Controlling drones thousands of miles away, performing remote surgeries or being immersed in video with no latency will also be a huge game changer. Those are some of the few things that make the fifth generation (5G) a revolution expected to be a thrust to the economy. To that end, the design and density of deployment of new networks is also changing becoming more dense, what introduces new challenges into play. What else will it add to previous generations? The MOOC about Ultra-dense networks for 5G and its evolution has been prepared by the researchers of an European MSCA ITN, named TeamUp5G, and introduces the most important technologies that support 5G mobile communications, with an emphasis on increasing capacity and reducing power. The content spans from aspects of communication technologies to use cases, prototyping and the future ahead, not forgetting issues like interference management, energy efficiency or spectrum management. The aim of the MOOC is to fill the gap in graduation and post-graduation learning on content related to emerging 5G technologies and its applications, including the future 6G. The target audience involves engineers, researchers, practitioners and students. This paper describes the content and the learning outcomes of the MOOC, the main tasks and resources involved in its creation, the joint contributions from the academic and non-academic sector, and aspects like copyright compliance, quality assurance, testing and details on communication and enrollment, followed by the discussion of the lessons learned. This work has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie ETN TeamUp5G, grant agreement No. 813391.

Proceedings of: 2022 IEEE Wireless Communications and Networking Conference (WCNC), 10-13 April 2022, Austin, USA. Reconfigurable Intelligent Surfaces (RISs) are an emerging technology in the evolution towards the Sixth Generation (6G) of mobile communications. They are capable of enhancing the overall system performance and extending the coverage of the existing cells. They are built by a large amount of low-cost meta-elements that can be configured by tuning their phase shifts, and hence, the channel response can be constructively combined and forwarded to some specific direction. Many algorithms have been proposed to obtain the optimum phase shifts, generally assuming a single-carrier system and/or a medium-size RIS to constrain the complexity of the optimization process. In this work, we propose a flexible and scalable unsupervised learning model, capable of obtaining the best phase shifts for any scenario. Our proposal is able to handle multi-carrier waveforms and very large-size RIS, considering both continuous and discrete phase shifts. Besides, we also propose the use of clustering to reduce further the complexity while maintaining the performance. A comparison in terms of achievable rate and time execution is provided in order to show the superiority of our proposal against the existing solutions. This work has been funded by the Spanish National projects IRENE-EARTH (PID2020-115323RB-C33 / AEI/ 10.13039/501100011033) and AMATISTA (CDTI IDI20200861).

Augmented reality (AR) has been presented lately as one of the key technology fields in which 5G networks can become a disruptive tool, raising interest from both industry and academia. The main goal of this article is to extend the current state of the art of distributed AR studies and implementations by extracting the main AR algorithms' offloading requirements individually. This extension is further achieved by depicting the data flow between these algorithms and their hardware requirements. From the obtained results, we estimate a preliminary set of network key performance indicators (KPIs) for a subset of three examples of distributed AR implementations highlighting the necessity of 5G technologies and their ecosystem to unveil the full potential of AR. Finally, based on these KPls, we propose a set of 5G configuration parameters for a successful distributed AR implementation. As most of the described algorithms are also used in virtual reality (VR) applications, our contributions can facilitate future distributed implementations of both AR and VR applications. This work has received funding from the European Union (EU) Horizon 2020 research and innovation programme under the Marie Skodowska-Curie ETN TeamUp5G, grant agreement no. 813391.

Ponencia presentada en la Jornada de Innovación Docente 2021: aprendizaje activo, celebrada el 6 de julio de 2021 en la Universidad Carlos III de Madrid.

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This poster has been accepted for presentation at the IEEE Communication Theory Workshop (IEEE CTW 2018 ), 15-16 May, 2018, Miramar Beach, Florida. Massive MIMO combined with OFDM are key techniques in the evolution of mobile communications. In this context, to the best of our knowledge, the channel estimation and the equalizers have never been jointly considered. We propose an alternative low-complexity method to compute the ZF equalizers, which consists of exchanging the order of the interpolation and computation of the equalizer. For massive MIMO, this strategy provides the same performance and considerably lower number of operations, compared to the traditional scheme. This work has been partly funded by projects MACHINE (TSI-100102-2015-17), ELISA (TEC2014-59255-C3-3-R) and TERESA-ADA (TEC2017-90093-C3-2-R) (MINECO/AEI/FEDER, UE).

Ponencia presentada en: XXX Simposium Nacional de la Unión Científica Internacional de Radio, los dias 2 y 4 septiembre 2015, en Pamplona (españa). Video services are expected to become more than 70% of the mobile traffic in 2020. Broadcast and multicast service is the most efficient mechanism to deliver the same content to many users. Not only focusing on venue casting, but also distributing many other media such as software updates and breaking news, 5G broadcasting is a key driver to achieve the spectral efficiency needed for the 1,000 times traffic growth that is expected for the upcoming years. Improvements in some areas, such as resource allocation techniques for broadcast/multicast services, are needed. The utilization of the Conventional Multicast Scheme (CMS) approach for multicast resource allocation presents intrinsic inefficiencies, because of the different channel conditions of the users which demand the service. This paper presents some resource allocation strategies based on the use of multicast subgroups. We propose a multicast resource allocation algorithm including memory, which results in improvements of the service throughput at the time a high fairness among the users is guaranteed. In addition, an algorithm of joint resource allocation among multicast and unicast transmissions is developed. This strategy allows the system to take advantage of the subframes reserved for each purpose by the Long Term Evolution (LTE) standard, looking for the best joint allocation of the available resources, and results in important improvements in the service throughput This work was supported in part by the Spanish Ministry of Economy and Competitiveness, National Plan for Scientific Research, Development and Technological Innovation (IN-NPACTO subprogram), LTExtreme project (IPT-2012-0525-430000), and the projects TEC2011-29006-C03-03 (GRE3NSYST) and TEC2014-59255-C3-3-R (ELISA). Publicada

Proceeding of: 2nd International Conference on Wireless Communication Systems and Networks (MIC-Wireless 2015), Barcelona, August 7th-9th 2015 This paper investigates the use of bit loading al- gorithms in order to use ESIM OFDM in frequency selective channels. This work focuses on maximizing the bit rate minimiz- ing the loss of spectral efficiency because of the insertion of idle subcarriers. Besides, the modified ESIM OFDM is generalized to support groups of subcarriers of arbitrary size based on the number of idle subcarriers. The effect of this generalization, as well as the new bit distribution after using bit loading, on the peak to average power ratio (PAPR) and the bit error rate (BER) are analyzed. Additionally a novel way to evaluate the BER in such a system is proposed. The proposed scheme is shown to outperform the original ESIM OFDM performance in terms of PAPR, at the cost of a small degradation of the BER. This improvement in the PAPR makes the proposed scheme a good candidate for Optical Wireless Communication (OWC) systems, and This work has been partly funded by project TEC2014-59255-C3-3-R (ELISA)

This proceeding at: The 22nd European Signal Processing Conference (EUSIPCO), took place 2014, September, 01-05 in Lisbon (Portugal). An interference aware precoding scheme based on limited channel state information at the transmitter (CSIT) is consid-ered for its use in the downlink of a cellular system. The transmitter precoder used is based on an MMSE-ZF criterion in order to maximize the user rate while the interference to other users is reduced. The proposed scheme also exploits the network topology, so that each BS can categorize the users into two groups, according to the level of interference that the BS is introducing in those users. On the receiver end, each user makes use of the whole channel state information at the receiver (CSIR) by employing an MMSE filter. This approach enables a reduction in the complexity of the system, while improving the performance of the whole network. This work has been partially funded by research projects COMONSENS (CSD2008-00010), and GRE3N (TEC2011-29006-C03-03. Publicado

Interference in a cellular network is one of the main impairments that needs to be overcome. Coordination among the Base Stations may enable the use of the interference to improve the transmission rate at the cost of increased computational complexity and more stringent backhaul and feedback requirements. Practical problems of global coordination can be reduced through clustering which, in turn, will introduce Out of Cluster Interference (OCI). OCI can seriously hamper the advantages brought by precoding techniques like Block Diagonalization (BD). In this work we propose a mixed transmission strategy using BD and Single User transmission that is able to overcome the problems introduced by the OCI, in combination with a low complexity scheduling algorithm that enables an increased transmission rate in a multiuser scenario.

This proceeding at: European Wireless 2014, took place 2014 Mai, 14-16, in Barcelona (España). The event web site of http://www.ew2014.org/ Mobile video service is one of the most increasing uses expected in future generation cellular networks, including multicast video services. Based upon Evolved Multimedia Broadcast and Multicast Service (eMBMS) available with 3rd Generation Partnership Project (3GPP) release 9, Long Term Evolution (LTE) can provide broadcast/multicast content delivery with a single-frequency network mode. This means sending the same multimedia content to a mass audience within a specific area. However, it is not always possible to use multicast transmission to every user because of their different channel conditions, so unicast transmission should also be used to fulfill Quality of Service (QoS) requirements for multicast services. This paper proposes a Joint Multicast/Unicast Scheduling (JMUS) strategy for multicast service delivery. This method is based on dynamic optimization at each LTE frame, obtaining the optimal Modulation and Coding Scheme (MCS) for multicast transmission, the optimal number of subframes reserved for multicast transmission and allocating the remaining resources using a unicast scheduling metric for guaranteed data-rate. The goal of the scheduling technique proposed is to maximize the overall throughput, guaranteeing a target bit rate for all the users in the area. A new JMUS with dynamic optimization is presented to improve QoS performance. Finally, a fast search algorithm is evaluated to approach the optimal values for dynamic optimization with an order of magnitude fewer iterations than using exhaustive search. This work was supported in part by the Spanish Min-istry of Economy and Competitiveness, National Plan for Scienti?c Research, Development and Technological Inno-vation (INNPACTO subprogram), LTExtreme project (IPT- 2012-0525-430000) and the subproject TEC2011-29006-C03-03 (GRE3N-SYST). Publicado

The proceeding at: 21st European Signal Processing Conference (EUSIPCO 2013), took place 2013, September 09-13, in Marrakech, Septiembre 2013. Block Diagonalization (BD) is a linear precoding transmission technique able to achieve full multiplexing gain in multiple antenna systems. In this work we present a Multiple-Input Multiple-Output (MIMO) implementation based on Orthogonal Frequency Division Multiplexing (OFDM) made up of a transmitter with 4 antennas and 2 users equipped with 2 antennas each one, which allows us to evaluate the performance of BD in indoor scenarios. First, the theoretic achievable rates are obtained for the measured channel in an offline evaluation. After that, the bit error rate performance is evaluated regarding the system sum throughput. To the best of our knowledge, this is the first time that BD performance is validated using a multiuser MIMO testbed. This work has been partially funded by research projects COMONSENS (CSD2008-000 1 0), and GRE3N (TEC20 11-29006-C03-02). Publicado

Audiovisuales: Entrevista 1ª parte. Disponible en: https://arcamm.uc3m.es/arcamm/# .-- Entrevista 2ª parte. Disponible en: https://arcamm.uc3m.es/arcamm/?item=dd05fdc9e25f37f2c047c1a699d56627 .-- Entrevista 3ª parte. Disponible en: https://arcamm.uc3m.es/arcamm/?item=15e5fc3a1fae74e560dd60fa31e1ef36 .-- Entrevista completa. Disponible en: http://www.youtube.com/watch?feature=player_embedded&v=i_BgPT0O_WM Internet es ya parte de la vida cotidiana. Las tecnologías de la información y las comunicaciones han transformado radicalmente el mundo de los negocios, la educación, la comunicación o el ocio, en apenas una década.

Audiovisulaes: Entrevista a Esther Arias, Oficina Española de Patentes y Marcas. Disponible en https://www.youtube.com/watch?v=K38IC0NDctE . La gestión interna de los derechos de propiedad industrial e intelectual procedentes de los resultados de la investigación desarrollada en la Universidad Carlos III de Madrid es competencia de su Parque Científico. Dependiente del vicerrectorado de Investigación, es el responsable de la transferencia de tecnología y conocimiento a las empresas.Un servicio de la UC3M es la plataforma ORIÓN-UC3M, en que la persona investigadora o gestora del grupo de investigación introduce, a medida que se producen, sus ofertas en la plataforma. Contiene: El Parque Científico UC3M, gestor de los derechos de propiedad industrial e intelectual (p. 22) .Los inventores opinan. La experiencia de proteger sus resultados con el Parque Científico UC3M / Valentín Miguel Moreno, Ana García–Armada (p. 23) .-- Más opiniones / Raúl Sánchez–Reíllo, Manuel Armenteros (p. 24).

Proceeding at: Opnetwork2013, took place 2013, August, 1-2, in Washington (USA) Mobile video is one of the most popular uses for mobile broadband networks. Based upon evolved Multimedia Broadcast Multicast Service (eMBMS) available with 3GPP Release 9, LTE can provide broadcast/multicast content delivery with a single-frequency network mode that sends the same multimedia content to a mass audience within a specific area. In this paper, we describe a performance analysis carried out for this type of network using OPNET Modeler. We propose a new algorithm to create, dynamically, Multicast-Broadcast Single Frequency Network (MBSFN) areas that will optimize the efficiency of multicast transmissions of events to a large number of users in a limited area. This work was supported in part by the National Scientific Research, Development and Technological Innovation, LTExtreme project (IPT-2012-0525-430000). Publicado

La ponencia presentada en: XXVIII Simposium Nacional de la Unión Científica Internacional de Radio. URSI 2013. Santiago de Compostela, 11-13 Sept. 2013. Mobile video is one of the most popular uses for mobile broadband networks. Based upon evolved Multimedia Broadcast Multicast Service (eMBMS) available with 3GPP release 9, LTE can provide broadcast/multicast content delivery with a single-frequency network mode that send the same multimedia content to mass audience within a specific area. In this paper, we carry out a Signal to Interference plus Noise Ratio (SINR) performance analysis for this type of networks, using OPNET Modeler tool. Several scenarios have been considered, with different number of users receiving multicast video data from the same source and different number of eNodeBs. This study includes the comparison of SINR in scenarios with 1, 3 and 7 different frequencies using multicast without MBMS or with MBMS SFN. The results show a comparison in the cell throughput between the different scenarios, as well as the performance obtained using different sizes of MBMS SFN areas. Este trabajo ha sido en parte financiado por el Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica, proyecto LTExtreme (IPT-2012- 0525-430000). Publicado

This proceeding at: Workshop on Small Cell Cooperative Communications, Lyon (Francia), 2-Mayo 2012.The event Web site at http://ic1004-iplan-2012.conf.citi-lab.fr/ Future cellular networks will be more dense and heterogeneous. A typical deployment will be based on micro, pico and femto cells. Under this scenario, novel interference management techniques such as network MIMO will be mandatory. However, it is usual to combine them with power allocation strategies to maximize the sum of the rates or minimize the power consumption. Those strategies are unfair at user level in heterogeneous networks and do not provide a "green" measure. In this work we propose some more equitable alternatives to the classical power allocation schemes and a strategy based on a green metric. Finally we compare the performance, in user spectral efficiency and power consumption terms, of these strategies in micro and femto cell deployments. This work has been partly funded by projects GRE3N TEC2011-29006-C03-03 and COMONSENS CSD2008-00010. Publicado

Publicado

El Grupo de Comunicaciones de la Universidad Carlos III de Madrid ha diseñado e implementado algoritmos para mejora de las prestaciones de los sistemas MIMO-OFDM. Esta tecnología es capaz de proporcionar comunicaciones inalámbricas con gran velocidad de transmisión. Los algoritmos desarrollados permiten, por una parte, la corrección de imperfecciones introducidas por los equipos de radio-frecuencia y, por otra, la adaptación de la transmisión a las características del canal.

Communications Group of University Carlos III of Madrid has designed and implemented algorithms for the improvement of the performance of MIMO-OFDM systems. This technology is capable of providing high data rate wireless communications. The developed algorithms allow, on one side, the correction of the imperfections introduced by radio-frequency equipment and, on the other side, adaptation of the transmission to the channel characteristics.

Publication in the conference proceedings of EUSIPCO, Poznan, Poland, 2007

This paper presents a preliminary study on some parameters of the Wind-Flex project which are to be determined, such as digital type modulation, multi-access techniques and requirements of amplifiers linearity and synthesisers phase noise. Orthogonal Frequency Division Multiplex seems to be the most appropriate modulation to reduce the channel fading effects. Further study shall be carried out in this field, as power and bit rate control in each OFDM sub-carrier are expected.

This paper analyses the characteristics of the propagation channel in several indoor scenarios at 5 GHz and 17 GHz. These two frequencies are candidates for the implementation of high capacity indoor wireless networks and the analysis will bring some insight into the advantages and disadvantages of the selection of each of them. Besides, power-delay profiles and coherence bandwidth are presented, that will lead us to the construction of simulation models to study modulation and coding trade-offs.

This paper analyzes frequency packing schemes applied to multibeam satellite systems. In order to simulate a realistic scenario we have taken into account the presence of co-channel interference and spectrum limitations. The results show that with low order modulations, e.g. QPSK and 8APSK, the frequency packing schemes outperform in terms of spectral eciency conventional single carrier schemes with high modulation orders up to 32APSK. However, the experimental validation carried out with the DVB-S2 modulation and coding (ModCod) schemes reveals that there is a gap between the maximum achievable rates and the throughput. This result highlights that new ModCod schemes have to be designed, so that frequency packing schemes perform closer to the theoretical bounds.

Mención Internacional en el título de doctor, La necesidad de tasas de transmisión más elevadas y una mayor eficiencia en las redes celulares es la principal motivación para considerar el uso de UFR. La coordinación entre BSs se hace necesaria, entonces, para compensar los problemas introducidos por la interferencia. La coordinación global de la red es demasiado compleja y, además, presenta limitaciones intrínsecas, que impiden su utilización en escenarios reales. La utilización de grupos reducidos de BSs es una alternativa para reducir los requisitos impuestos por la coordinación. Como consecuencia de la agrupación, aparece OCI, la cual perjudica seriamente las comunicaciones. Este trabajo se centra en BD, una técnica de precodificación lineal que combina unas buenas prestaciones con una complejidad relativamente baja. Sin embargo, la interferencia empeora notablemente su funcionamiento. En esta tesis se estudia el canal descendente de una red celular conglomerada, donde se usa BD para coordinar las BSs que forman cada grupo. Se analiza la tasa media obtenible como función de múltiples parámetros del escenario. De especial interés es la dependencia con el tamaño de las agrupaciones, de donde se desprende que existe un tamaño óptimo para los grupos de BSs, por encima del cual no se obtienen mejoras significativas. La equidad del sistema se estudia en presencia de OCI, también como función de diversos parámetros del escenario, como puede ser la asignación de potencia. Se propone una estrategia mixta de transmisión, que combina BD con procesado SU, como mecanismo para combatir las dificultades introducidas por la interferencia que no se gestiona. La estrategia consiste en dos fases: • Los usuarios deciden localmente qué estrategia prefieren para la transmisión, y envían esta información a las BSs. • Las BSs utilizan las decisiones recibidas para planificar las transmisiones, de modo que se pueda optimizar el funcionamiento de la red. El resultado de la estrategia propuesta es una mejora de las prestaciones de BD en presencia de OCI, especialmente para los usuarios más desfavorecidos. Esto se traduce en que, adicionalmente, el sistema se vuelve más justo, al mismo tiempo que el rendimiento de la red aumenta., The need for higher data rates and higher efficiency in cellular networks motivates the use of Universal Frequency Reuse (UFR). Coordination among Base Stations (BSs) is required then to alleviate the performance penalty due to the interference. Global coordination is too complex and has inherent limitations that prevents it from being used in real world scenarios. Clusters of a reduced number of BSs can be considered in order to ease off the requirements of coordination. As a result, Other Cluster Interference (OCI) appears, affecting negatively the communications. This work focuses on Block Diagonalization (BD), a linear precoding technique that combines a good theoretical performance with a relatively low complexity. However, the unwanted interference seriously impacts the results obtained using BD. This thesis studies the downlink of a clustered cellular network, where BD is used to coordinate the BS within each cluster. The mean achievable rate is analyzed as a function of several scenario parameters. Of particular interest is the dependence on the cluster size, which yields that there is an optimum cluster size, beyond which no significant gain is obtained. Fairness considerations are analyzed in the presence of OCI, also studied as a function of scenario parameters such as the power allocation. A mixed strategy using BD and Single User (SU) processing is proposed as a means to overcome the impairment of the unhandled interference. The transmission consists of two stages: • Users locally decide which transmission strategy they prefer and send this information to the BSs. • BSs use the decisions of all users to schedule them for transmission so that the performance of the network is optimized. The result of the proposed strategy is an improvement in the performance of BD in the presence of OCI, especially for the users experiencing the worst conditions. This means that the fairness of the system is also increased, along with the overall performance of the network., Programa Oficial de Doctorado en Multimedia y Comunicaciones, Presidente: Lajos Hanzo.- Secretario: Raquel Perez Leal.- Vocal: Atilio Manuel da Silva Gameiro

Mención Internacional en el título de doctor Nowadays, it is nearly impossible to think of a service that does not rely on wireless communications. By the end of 2022, mobile internet represented a 60% of the total global online traffic. There is an increasing trend both in the number of subscribers and in the traffic handled by each subscriber. Larger data rates, smaller extreme-to-extreme (E2E) delays and greater number of devices are current interests for the development of mobile communications. Furthermore, it is foreseen that these demands should also be fulfilled in scenarios with stringent conditions, such as very fast varying wireless communications channels (either in time or frequency) or scenarios with power constraints, mainly found when the equipment is battery powered. Since most of the wireless communications techniques and standards rely on the fact that the wireless channel is somehow characterized or estimated to be pre or post-compensated in transmission (TX) or reception (RX), there is a clear problem when the channels vary rapidly or the available power is constrained. To estimate the wireless channel and obtain the so-called channel state information (CSI), some of the available resources (either in time, frequency or any other dimension), are utilized by including known signals in the TX and RX typically known as pilots, thus avoiding their use for data transmission. If the channels vary rapidly, they must be estimated many times, which results in a very low data efficiency of the communications link. Also, in case the power is limited or the wireless link distance is large, the resulting signal-tointerference- plus-noise ratio (SINR) will be low, which is a parameter that is directly related to the quality of the channel estimation and the performance of the data reception. This problem is aggravated in massive multiple-input multiple-output (massive MIMO), which is a promising technique for future wireless communications since it can increase the data rates, increase the reliability and cope with a larger number of simultaneous devices. In massive MIMO, the base station (BS) is typically equipped with a large number of antennas that are coordinated. In these scenarios, the channels must be estimated for each antenna (or at least for each user), and thus, the aforementioned problem of channel estimation aggravates. In this context, algorithms and techniques for massive MIMO without CSI are of interest. This thesis main topic is non-coherent massive multiple-input multiple-output (NC-mMIMO) which relies on the use of differential M-ary phase shift keying (DMPSK) and the spatial diversity of the antenna arrays to be able to detect the useful transmitted data without CSI knowledge. On the one hand, hybrid schemes that combine the coherent and non-coherent schemes allowing to get the best of both worlds are proposed. These schemes are based on distributing the resources between non-coherent (NC) and coherent data, utilizing the NC data to estimate the channel without using pilots and use the estimated channel for the coherent data. On the other hand, new constellations and user allocation strategies for the multi-user scenario of NC-mMIMO are proposed. The new constellations are better than the ones in the literature and obtained using artificial intelligence techniques, more concretely evolutionary computation. This work has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie ETN TeamUp5G, grant agreement No. 813391. The PhD student was the Early Stage Researcher (ESR) number 2 of the project. This work has also received funding from the Spanish National Project IRENE-EARTH (PID2020-115323RB-C33) (MINECO/AEI/FEDER, UE), which funded the work of some coauthors. Programa de Doctorado en Multimedia y Comunicaciones por la Universidad Carlos III de Madrid y la Universidad Rey Juan Carlos Presidente: Luis Castedo Ribas.- Secretario: Matilde Pilar Sánchez Fernández.- Vocal: Eva Lagunas Targarona