Channel estimation techniques for next generation mobile communication systems

Chen Hu, Kun

Publication:
Channel estimation techniques for next generation mobile communication systems

dc.contributor.advisor	García-Armada, Ana
dc.contributor.author	Chen Hu, Kun
dc.contributor.departamento	UC3M. Departamento de Teoría de la Señal y Comunicaciones	es
dc.date.accessioned	2020-02-04T09:24:30Z
dc.date.available	2020-02-04T09:24:30Z
dc.date.issued	2019-07
dc.date.submitted	2019-07-08
dc.description	Mención Internacional en el título de doctor
dc.description.abstract	We are witnessing a revolution in wireless technology, where the society is demanding new services, such as smart cities, autonomous vehicles, augmented reality, etc. These challenging services not only are demanding an enormous increase of data rates in the range of 1000 times higher, but also they are real-time applications with an important delay constraint. Furthermore, an unprecedented number of different machine-type devices will be also connected to the network, known as Internet of Things (IoT), where they will be transmitting real-time measurements from different sensors. In this context, the Third Generation Partnership Project (3GPP) has already developed the new Fifth Generation (5G) of mobile communication systems, which should be capable of satisfying all the requirements. Hence, 5G will provide three key aspects, such as: enhanced mobile broad-band (eMBB) services, massive machine type communications (mMTC) and ultra reliable low latency communications (URLLC). In order to accomplish all the mentioned requirements, it is important to develop new key radio technologies capable of exploiting the wireless environment with a higher efficiency. Orthogonal frequency division multiplexing (OFDM) is the most widely used waveform by the industry, however, it also exhibits high side lobes reducing considerably the spectral efficiency. Therefore, filter-bank multi-carrier combined with offset quadrature amplitude modulation (FBMC-OQAM) is a waveform candidate to replace OFDM due to the fact that it provides extremely low out-ofband emissions (OBE). The traditional spectrum frequencies range is close to saturation, thus, there is a need to exploit higher bands, such as millimeter waves (mm-Wave), making possible the deployment of ultra broad-band services. However, the high path loss in these bands increases the blockage probability of the radio-link, forcing us to use massive multiple-input multiple-output (MIMO) systems in order to increase either the diversity or capacity of the overall link. All these emergent radio technologies can make 5G a reality. However, all their benefits can be only exploited under the knowledge and availability of the channel state information (CSI) in order to compensate the effects produced by the channel. The channel estimation process is a well known procedure in the area of signal processing for communications, where it is a challenging task due to the fact that we have to obtain a good estimator, maintaining at the same time the efficiency and reduced complexity of the system and obtaining the results as fast as possible. In FBMC-OQAM, there are several proposed channel estimation techniques, however, all of them required a high number of operations in order to deal with the self-interference produced by the prototype filter, hence, increasing the complexity. The existing channel estimation and equalization techniques for massive MIMO are in general too complex due to the large number of antennas, where we must estimate the channel response of each antenna of the array and perform some prohibitive matrix inversions to obtain the equalizers. Besides, for the particular case of mm-Wave, the existing techniques either do not adapt well to the dynamic ranges of signal-to-noise ratio (SNR) scenarios or they assume some approximations which reduce the quality of the estimator. In this thesis, we focus on the channel estimation for different emerging techniques that are capable of obtaining a better performance with a lower number of operations, suitable for low complexity devices and for URLLC. Firstly, we proposed new pilot sequences for FBMC-OQAM enabling the use of a simple averaging process in order to obtain the CSI. We show that our technique outperforms the existing ones in terms of complexity and performance. Secondly, we propose an alternative low-complexity way of computing the precoding/postcoding equalizer under the scenario of massive MIMO, keeping the quality of the estimator. Finally, we propose a new channel estimation technique for massive MIMO for mm-Wave, capable of adapting to very variable scenarios in terms of SNR and outperforming the existing techniques. We provide some analysis of the mean squared error (MSE) and complexity of each proposed technique. Furthermore, some numerical results are given in order to provide a better understanding of the problem and solutions.	en
dc.description.degree	Programa de Doctorado en Multimedia y Comunicaciones por la Universidad Carlos III de Madrid y la Universidad Rey Juan Carlos	es
dc.description.responsability	Presidente: Antonia María Tulino.- Secretario: Máximo Morales Céspedes.- Vocal: Octavia A. Dobre	es
dc.identifier.uri	https://hdl.handle.net/10016/29609
dc.language.iso	eng	en
dc.relation.haspart	https://doi.org/10.1109/TVT.2018.2861995
dc.relation.haspart	https://doi.org/10.1109/VTCSpring.2019.8746436
dc.relation.haspart	https://doi.org/10.1109/ICCW.2019.8757027
dc.relation.ispartof	https://doi.org/10.1109/ACCESS.2019.2909405
dc.relation.ispartof	https://doi.org/10.1109/PIMRC.2016.7794702
dc.relation.ispartof	https://doi.org/10.1109/VTCSpring.2018.8417533
dc.relation.ispartof	https://doi.org/10.1109/SPAWC.2018.8445894
dc.relation.ispartof	https://doi.org/10.1109/VTCFall.2017.8287938
dc.relation.ispartof	https://doi.org/10.1109/ICC.2019.8761447
dc.rights	Atribución-NoComercial-SinDerivadas 3.0 España	*
dc.rights.accessRights	open access	en
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/es/	*
dc.subject.eciencia	Telecomunicaciones	es
dc.subject.other	Mobile communications systems	en
dc.subject.other	Channel estimation	en
dc.subject.other	Wireless technology	en
dc.subject.other	FBMC/OQAM	en
dc.subject.other	Filter-bank multi-carrier	en
dc.subject.other	Ofset quadrature amplitude modulation	en
dc.subject.other	5G mobile communication	en
dc.subject.other	MIMO-OFDM (Multiple Input Multiple Output –Orthogonal Frequency Division Multiplexing)	en
dc.title	Channel estimation techniques for next generation mobile communication systems	en
dc.type	doctoral thesis	*
dspace.entity.type	Publication