34 research outputs found
CPM-SC-IFDMA--A Power Efficient Transmission Scheme for Uplink LTE
In this thesis we have proposed a power efficient transmission scheme, CPM-SC-IFDMA, for uplink LTE. In uplink LTE, efficiency of the transmitter power amplier is a major concern, as the transmitter is placed in the mobile device which has limited power supply. The proposed scheme, CPM-SC-IFDMA, combines the key advantages of CPM (continuous phase modulation) with SC-IFDMA (single carrier frequency division multiple access with interleaved subcarrier mapping) in order to increase the power amplier efficiency of the transmitter. In this work, we have analyzed the bit error rate (BER) performance of the proposed scheme in LTE specied channels. The BER performance of two CPM-SC-IFDMA scheme are compared with that of a LTE specied transmission scheme, QPSK-LFDMA (QPSK modulated SC-FDMA with localized subcarrier mapping), combined with convolutional coding (CC-QPSK-LFDMA). We first show that CPM-SC-IFDMA has a much higher power efficiency than CC-QPSK-LFDMA by simulating the PAPR (peak-to-average-power-ratio) plots. Then, using the data from the PAPR plots and the conventional BER plots (BER as a function of signal-to-noise-ratio), we show that, when the net BER, obtained by compensating for the power efficiency loss, is considered, CPM-SC-IFDMA has a superior performance relative to CC-QPSK-LFDMA by up to 3.8 dB, in the LTE specified channels
Implementação de um sistema de comunicações móveis para o Uplink
Mestrado em Engenharia Electrónica e TelecomunicaçõesÉ evidente que actualmente cada vez mais a internet móvel está presente na
vida das sociedades. Hoje em dia é relativamente fácil estar ligado à internet
sempre que se quiser, independentemente do lugar onde se encontra
(conceito: anytime and anywhere). Desta forma existe um número crescente
de utilizadores que acedem a serviços e aplicações interactivas a partir dos
seus terminais móveis. Há, portanto, uma necessidade de adaptar o mundo
das telecomunicações a esta nova realidade, para isso é necessário
implementar novas arquitecturas que sejam capazes de fornecer maior largura
de banda e reduzir os atrasos das comunicações, maximizando a utilização
dos recursos disponíveis do meio/rede e melhorando assim a experiência do
utilizador final.
O LTE representa uma das tecnologias mais avançadas e de maior relevância
para o acesso sem fios em banda larga de redes celulares. OFDM é a
tecnologia base que está por traz da técnica de modulação, bem como as
tecnologias adjacentes, OFDMA e SC-FDMA, usadas especificamente no LTE
para a comunicação de dados descendente (downlink) ou ascendente (uplink),
respectivamente. A implementação de múltiplas antenas em ambos os
terminais, potenciam ainda mais o aumento da eficiência espectral do meio
rádio permitindo atingir grandes taxas de transmissão de dados.
Nesta dissertação é feito o estudo, implementação e avaliação do
desempenho da camada física (camada 1 do modelo OSI) do LTE, no entanto
o foco será a comunicação de dados ascendente e a respectiva técnica de
modelação, SC-FDMA. Foi implementada uma plataforma de simulação
baseada nas especificações do LTE UL onde foram considerandos diferentes
esquemas de antenas. Particularmente para o esquema MIMO, usou-se a
técnica de codificação no espaço-frequência proposta por Alamouti. Foram
também implementados vários equalizadores.
Os resultados provenientes da simulação demonstram tanto a eficiência dos
diversos modos de operação em termos da taxa de erro, como o excelente
funcionamento de processos de mapeamento e equalização, que visam
melhorar a taxa de recepção de dados.It is clear that mobile Internet is present in the life of societies. Nowadays it is
relatively easy to be connected to the internet whenever you want, no matter
where you are (concept: anytime and anywhere). Thus, there are a growing
number of users accessing interactive services and applications from their
handsets. Therefore, there is a need to adapt the world of telecommunications
to this new reality, for that it is necessary to implement new architectures that
are able to provide higher bandwidth and reduce communication delays,
maximizing use of available resources in the medium/network and thereby
improving end-user experience.
LTE represents one of the most advanced architectures and most relevant to
wireless broadband cellular networks. OFDM is the technology that is behind
the modulation technique and the underlying technologies, OFDMA and SCFDMA,
used specifically in LTE for data communication downward (downlink)
or upward (uplink), respectively. The implementation of multiple antennas at
both ends further potentiate the increase of spectral efficiency allowing to
achieve high rates of data transmission.
In this dissertation is done the study, implementation and performance
evaluation of the physical layer (OSI Layer 1) of the LTE, but the focus will be
communication and its upstream data modeling technique, SC-FDMA. We
implemented a simulation platform based on LTE UL specifications where were
considered different antenna schemes. Particularly for the MIMO scheme, we
used the technique of space-frequency coding proposed by Alamouti. We also
implemented several equalizers.
The results from the simulation demonstrate both the efficiency of different
modes of operation in terms of error rate, as the excellent operation of mapping
processes and equalization, designed to improve the rate of receiving data
Real-Time Localization Using Software Defined Radio
Service providers make use of cost-effective wireless solutions to identify, localize, and possibly track users using their carried MDs to support added services, such as geo-advertisement, security, and management. Indoor and outdoor hotspot areas play a significant role for such services. However, GPS does not work in many of these areas. To solve this problem, service providers leverage available indoor radio technologies, such as WiFi, GSM, and LTE, to identify and localize users. We focus our research on passive services provided by third parties, which are responsible for (i) data acquisition and (ii) processing, and network-based services, where (i) and (ii) are done inside the serving network. For better understanding of parameters that affect indoor localization, we investigate several factors that affect indoor signal propagation for both Bluetooth and WiFi technologies. For GSM-based passive services, we developed first a data acquisition module: a GSM receiver that can overhear GSM uplink messages transmitted by MDs while being invisible. A set of optimizations were made for the receiver components to support wideband capturing of the GSM spectrum while operating in real-time. Processing the wide-spectrum of the GSM is possible using a proposed distributed processing approach over an IP network. Then, to overcome the lack of information about tracked devices’ radio settings, we developed two novel localization algorithms that rely on proximity-based solutions to estimate in real environments devices’ locations. Given the challenging indoor environment on radio signals, such as NLOS reception and multipath propagation, we developed an original algorithm to detect and remove contaminated radio signals before being fed to the localization algorithm. To improve the localization algorithm, we extended our work with a hybrid based approach that uses both WiFi and GSM interfaces to localize users. For network-based services, we used a software implementation of a LTE base station to develop our algorithms, which characterize the indoor environment before applying the localization algorithm. Experiments were conducted without any special hardware, any prior knowledge of the indoor layout or any offline calibration of the system
D6.3 Intermediate system evaluation results
The overall purpose of METIS is to develop a 5G system concept that fulfil s the requirements of the beyond-2020 connected information society and to extend today’s wireless communication systems for new usage cases. First, in this deliverable an updated view on the
overall METIS 5G system concept is presented.
Thereafter, simulation results for the most promising technology components supporting the METIS 5G system concept are reported.
Finally, s
imulation results are presented for
one
relevant
aspect of each Horizontal Topic:
Direct Device
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to
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Device Communication, Massive Machine Communication, Moving Networks,
Ultra
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Dense Networks, and Ultra
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Reliable Communication.Popovski, P.; Mange, G.; Fertl, P.; Gozálvez - Serrano, D.; Droste, H.; Bayer, N.; Roos, A.... (2014). D6.3 Intermediate system evaluation results. http://hdl.handle.net/10251/7676