67 research outputs found
Dynamic Channel Modeling for Indoor Millimeter-Wave Propagation Channels Based on Measurements
In this contribution, a recently conducted measurement campaign for indoor millimeter-wave propagation channels is introduced. A vector network analyzer (VNA)-based channel sounder was exploited to record the channel characteristics at the frequency band from 28-30 GHz. A virtual uniform circular array (UCA) with a radius of 0.25m was formed using a rotator with 360 steps. Moreover, by taking advantage of fiber-optic technique applied in the channel sounder, measurements at 50 positions were performed from an indoor hall to an indoor corridor along a long pre-defined route. A low-complexity highresolution propagation estimation (HRPE) algorithm is exploited to estimate the propagation parameters of multipath components (MPCs). Based on the HRPE estimation results, a novel clustering identification and tracking algorithm is proposed to trace clusters. Composite channel characteristics, cluster-level characteristics and dynamic (or birth-death) behaviours of the clusters are investigated, which constitute a dynamic model for the indoor millimeter-wave channel
Optimization of Spectrum Management in Massive Array Antenna Systems with MIMO
Fifth generation (5G), is being considered as a revolutionary technology in the telecommunication
domain whose the challenges are mainly to achieve signal quality and great ability to
work with free spectrum in the millimetre waves. Besides, other important innovations are the
introduction of a more current architecture and the use of multiple antennas in transmission
and reception. Digital communication using multiple input and multiple output (MIMO) wireless
links has recently emerged as one of the most significant technical advances in modern communications.
MIMO technology is able to offer a large increase in the capacity of these systems,
without requiring a considerable increase in bandwidth or power required for transmission.
This dissertation presents an overview of theoretical concepts of MIMO systems. With such a
system a spatial diversity gain can be obtained by using space-time codes, which simultaneously
exploit the spatial domain and the time domain. SISO, SIMO and MISO systems are differentiated
by their channel capacity and their configuration in relation to the number of antennas in the
transmitter/receiver. To verify the effectiveness of the MIMO systems a comparison between the
capacity of SISO and MIMO systems has been performed using the Shannon’s principles. In the
MIMO system some variations in the number of antennas arrays have been considered, and the
superiority of transmission gains of the MIMO systems have been demonstrated. Combined with
millimetre waves (mmWaves) technology, massive MIMO systems, where the number of antennas
in the base station and the number of users are large, is a promising solution.
SDR implementations have been performed considering a platform with Matlab code applied to
MIMO 2x2 Radio and Universal Software Peripheral Radio (USRP). A detailed study was initially
conducted to analyze the architecture of the USRP. Complex structures of MIMO systems can
be simplified by using mathematical methods implemented in Matlab for the synchronization of
the USRP in the receiver side. SISO transmission and reception techniques have been considered
to refine the synchronization (with 16-QAM), thus facilitating the future implementation of the
MIMO system. OpenAirInterface has been considered for 4G and 5G implementations of actual
mobile radio communication systems. Together with the practical MIMO, this type of solution is
the starting point for future hardware building blocks involving massive MIMO systems.A quinta geração (5G) está sendo considerada uma tecnologia revolucionária no setor de telecomunicações,
cujos desafios são principalmente a obtenção de qualidade de sinal e grande capacidade
de trabalhar com espectro livre nas ondas milimétricas. Além disso, outras inovações
importantes são a introdução de uma arquitetura mais atual e o uso de múltiplas antenas em
transmissão e recepção. A comunicação digital usando ligaçõe sem fio de múltiplas entradas e
múltiplas saídas (MIMO) emergiu recentemente como um dos avanços técnicos mais significativos
nas comunicações modernas. A tecnologia MIMO é capaz de oferecer um elevado aumento na
capacidade, sem exigir um aumento considerável na largura de banda ou potência transmitida.
Esta dissertação apresenta uma visão geral dos conceitos teóricos dos sistemas MIMO. Com esses
sistemas, um ganho de diversidade espacial pode ser obtido utilizando códigos espaço-tempo
reais. Os sistemas SISO, SIMO e MISO são diferenciados pela capacidade de seus canais e a sua
configuração em relação ao número de antenas no emissor/receptor. Para verificar a eficiência
dos sistemas MIMO, realizou-se uma comparação entre a capacidade dos sistemas SISO e MIMO
utilizado os princípios de Shannon. Nos sistemas MIMO condecideraram-se algumas variações no
número de agregados de antenas, e a superioridade dos ganhos de transmissão dos sistemas MIMO
foi demonstrada. Combinado com a tecnologia de ondas milimétricas (mmWaves), os sistemas
massivos MIMO, onde o número de antenas na estação base e o número de usuários são grandes,
são uma solução promissora.
As implementações do SDR foram realizadas considerando uma plataforma com código Matlab
aplicado aos rádios MIMO 2x2 e Universal Software Peripheral Radio (USRP). Um estudo detalhado
foi inicialmente conduzido para analisar a arquitetura da USRP. Estruturas complexas de sistemas
MIMO podem ser simplificadas usando métodos matemáticos implementados no Matlab para a
sincronização do USRP no lado do receptor. Consideraram-se técnicas de transmissão e recepção
SISO para refinar a sincronização (com 16-QAM), facilitando assim a implementação futura do
sistema MIMO . Considerou-se o OpenAirInterface para implementações 4G e 5G de sistemas
reais de comunicações móveis. Juntamente com o MIMO na pratica, este tipo de solução é
o ponto de partida para futuros blocos de construção de hardware envolvendo sistemas MIMO
massivos
5G Mobile Phone Network Introduction in Colombia
This research received support from the AUIP (Iberoamerican University Association for
Postgraduate Studies).The authors would like to thank the following members of Ericsson and Nokia
Company for their valuable technological support in relation to the deployment of 5G networks in
Colombia and Latin America. To Ericsson Company: Fabian Monge, Head of Networks & Managed
Services Sales LATAM North—Ericsson, Andrés Quintero Arango, Country Manager Colombia—
Ericsson, Camilo Beltrán, RAN Sales Domain Manager—Ericsson, Tatiana Dimian, Technical &
Solution Sales Colombia—Ericsson. To Nokia Company: Juan Gabriel Mariño Pedroza, Presales
Director & Business Development Colombia—Nokia.The deployment of the 5G mobile network is currently booming, offering commercially
available services that improve network performance metrics by minimizing network latency in
countries such as the USA, China, and Korea. However, many countries around the world are still in
the pilot phase promoted and regulated by government agencies. This is the case in Colombia, where
the assignment of the first 5G band is planned for the third quarter of 2021. By analyzing the results
of the pilot phase and the roadmap of the Colombian Ministry of Information and Communication
Technologies (MinTIC), we can determine the main issues, which contribute to the deployment of
5G mobile technology as well as the plans to achieve a 5G stand-alone network from 4G networks.
This is applicable to other countries in Latin America and the world. Then, our objective is to
synthesize and share the most important concepts of 5G mobile technology such as the MIMO
(multiple input/multiple output) antenna, RAN (Radio Access Network), C-RAN (Centralised-RAN),
and frequency bands, and evaluate the current stage of its introduction in Colombia.AUIP (Iberoamerican University Association for
Postgraduate Studies
Terahertz Communications and Sensing for 6G and Beyond: A Comprehensive View
The next-generation wireless technologies, commonly referred to as the sixth
generation (6G), are envisioned to support extreme communications capacity and
in particular disruption in the network sensing capabilities. The terahertz
(THz) band is one potential enabler for those due to the enormous unused
frequency bands and the high spatial resolution enabled by both short
wavelengths and bandwidths. Different from earlier surveys, this paper presents
a comprehensive treatment and technology survey on THz communications and
sensing in terms of the advantages, applications, propagation characterization,
channel modeling, measurement campaigns, antennas, transceiver devices,
beamforming, networking, the integration of communications and sensing, and
experimental testbeds. Starting from the motivation and use cases, we survey
the development and historical perspective of THz communications and sensing
with the anticipated 6G requirements. We explore the radio propagation, channel
modeling, and measurements for THz band. The transceiver requirements,
architectures, technological challenges, and approaches together with means to
compensate for the high propagation losses by appropriate antenna and
beamforming solutions. We survey also several system technologies required by
or beneficial for THz systems. The synergistic design of sensing and
communications is explored with depth. Practical trials, demonstrations, and
experiments are also summarized. The paper gives a holistic view of the current
state of the art and highlights the issues and challenges that are open for
further research towards 6G.Comment: 55 pages, 10 figures, 8 tables, submitted to IEEE Communications
Surveys & Tutorial
Deep Learning Aided Parametric Channel Covariance Matrix Estimation for Millimeter Wave Hybrid Massive MIMO
Millimeter-wave (mmWave) channels, which occupy frequency ranges much higher
than those being used in previous wireless communications systems, are utilized
to meet the increased throughput requirements that come with 5G communications.
The high levels of attenuation experienced by electromagnetic waves in these
frequencies causes MIMO channels to have high spatial correlation. To attain
desirable error performances, systems require knowledge about the channel
correlations. In this thesis, a deep neural network aided method is proposed
for the parametric estimation of the channel covariance matrix (CCM), which
contains information regarding the channel correlations. When compared to some
methods found in the literature, the proposed method yields satisfactory
performance in terms of both computational complexity and channel estimation
errors.Comment: M.Sc. Thesis, published at:
https://open.metu.edu.tr/handle/11511/9319
5G Mobile Phone Network Introduction in Colombia
The deployment of the 5G mobile network is currently booming, offering commercially available services that improve network performance metrics by minimizing network latency in countries such as the USA, China, and Korea. However, many countries around the world are still in the pilot phase promoted and regulated by government agencies. This is the case in Colombia, where the assignment of the first 5G band is planned for the third quarter of 2021. By analyzing the results of the pilot phase and the roadmap of the Colombian Ministry of Information and Communication Technologies (MinTIC), we can determine the main issues, which contribute to the deployment of 5G mobile technology as well as the plans to achieve a 5G stand-alone network from 4G networks. This is applicable to other countries in Latin America and the world. Then, our objective is to synthesize and share the most important concepts of 5G mobile technology such as the MIMO (multiple input/multiple output) antenna, RAN (Radio Access Network), C-RAN (Centralised-RAN), and frequency bands, and evaluate the current stage of its introduction in Colombia
Study, Measurements and Characterisation of a 5G system using a Mobile Network Operator Testbed
The goals for 5G are aggressive. It promises to deliver enhanced end-user experience
by offering new applications and services through gigabit speeds, and significantly
improved performance and reliability. The enhanced mobile broadband (eMBB) 5G use
case, for instance, targets peak data rates as high as 20 Gbps in the downlink (DL) and
10 Gbps in the uplink (UL).
While there are different ways to improve data rates, spectrum is at the core of enabling
higher mobile broadband data rates. 5G New Radio (NR) specifies new frequency
bands below 6 GHz and also extends into mmWave frequencies where more
contiguous bandwidth is available for sending lots of data. However, at mmWave
frequencies, signals are more susceptible to impairments. Hence, extra consideration is
needed to determine test approaches that provide the precision required to accurately
evaluate 5G components and devices.
Therefore, the aim of the thesis is to provide a deep dive into 5G technology, explore its
testing and validation, and thereafter present the OTE (Hellenic Telecommunications
Organisation) 5G testbed, including measurement results obtained and its characterisation based on key performance indicators (KPIs)
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