1,139 research outputs found
EVEREST IST - 2002 - 00185 : D23 : final report
Deliverable públic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version
Final report on the evaluation of RRM/CRRM algorithms
Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin
Situation awareness based automatic basestation detection and coverage reconfiguration in 3G systems
Performance Analysis of Micro Unmanned Airborne Communication Relays for Cellular Networks
This paper analyses the potential of utilising small unmanned-aerial-vehicles
(SUAV) as wireless relays for assisting cellular network performance. Whilst
high altitude wireless relays have been investigated over the past 2 decades,
the new class of low cost SUAVs offers new possibilities for addressing local
traffic imbalances and providing emergency coverage.We present field-test
results from an SUAV test-bed in both urban and rural environments. The results
show that trough-to-peak throughput improvements can be achieved for users in
poor coverage zones. Furthermore, the paper reinforces the experimental study
with large-scale network analysis using both stochastic geometry and multi-cell
simulation results.Comment: conferenc
Terminal LTE flexível
Mstrado em Engenharia Eletrónica e TelecomunicaçõesAs redes móveis estão em constante evolução. A geração atual (4G) de
redes celulares de banda larga e representada pelo standard Long Term
Evolution (LTE), definido pela 3rd Generation Partnership Project (3GPP).
Existe uma elevada procura/uso da rede LTE, com um aumento exponencial
do número de dispositivos móveis a requerer uma ligação à Internet de alto
débito. Isto pode conduzir à sobrelotação do espetro, levando a que o sinal
tenha que ser reforçado e a cobertura melhorada em locais específicos, tal
como em grandes conferências, festivais e eventos desportivos. Por outro
lado, seria uma vantagem importante se os utilizadores pudessem continuar
a usar os seus equipamentos e terminais em situações onde o acesso a redes
4G é inexistente, tais como a bordo de um navio, eventos esporádicos em
localizações remotas ou em cenários de catástrofe, em que as infraestruturas
que permitem as telecomunicações foram danificadas e a cobertura
temporária de rede pode ser decisiva em processos de salvamento. Assim
sendo, existe uma motivação clara por trás do desenvolvimento de uma
infraestrutura celular totalmente reconfigurável e que preencha as características mencionadas anteriormente.
Uma possível abordagem consiste numa plataforma de rádio definido por
software (SDR), de código aberto, que implementa o standard LTE e corre
em processadores de uso geral (GPPs), tornando possível construir uma rede
completa investindo somente em hardware - computadores e front-ends de
radiofrequência (RF). Após comparação e análise de várias plataformas LTE
de código aberto foi selecionado o OpenAirInterface (OAI) da EURECOM,
que disponibiliza uma implementação compatível com a Release 8.6 da
3GPP (com parte das funcionalidades da Release 10).
O principal objectivo desta dissertação é a implementação de um User
Equipment (UE) flexível, usando plataformas SDR de código aberto que corram
num computador de placa única (SBC) compacto e de baixa potência,
integrado com um front-end de RF - Universal Software Radio Peripheral
(USRP). A transmissão de dados em tempo real usando os modos de duplexagem
Time Division Duplex (TDD) e Frequency Division Duplex (FDD) é suportada e a reconfiguração de certos parâmetros é permitida, nomeadamente
a frequência portadora, a largura de banda e o número de Resource
Blocks (RBs) usados. Além disso, é possível partilhar os dados móveis LTE
com utilizadores que estejam próximos, semelhante ao que acontece com
um hotspot de Wi-Fi. O processo de implementação é descrito, incluindo
todos os passos necessários para o seu desenvolvimento, englobando o port
do UE de um computador para um SBC. Finalmente, a performance da rede
é analisada, discutindo os valores de débitos obtidos.Mobile networks are constantly evolving. 4G is the current generation of
broadband cellular network technology and is represented by the Long Term
Evolution (LTE) standard, de ned by 3rd Generation Partnership Project
(3GPP). There's a high demand for LTE at the moment, with the number
of mobile devices requiring an high-speed Internet connection increasing exponentially.
This may overcrowd the spectrum on the existing deployments
and the signal needs to be reinforced and coverage improved in speci c sites,
such as large conferences, festivals and sport events. On the other hand,
it would be an important advantage if users could continue to use their
equipment and terminals in situations where cellular networks aren't usually
available, such as on board of a cruise ship, sporadic events in remote
locations, or in catastrophe scenarios in which the telecommunication infrastructure
was damaged and the rapid deployment of a temporary network
can save lives. In all of these situations, the availability of
exible and easily
deployable cellular base stations and user terminals operating on standard
or custom bands would be very desirable. Thus, there is a clear motivation
for the development of a fully recon gurable cellular infrastructure solution
that ful lls these requirements.
A possible approach is an open-source, low-cost and low maintenance
Software-De ned Radio (SDR) software platform that implements the LTE
standard and runs on General Purpose Processors (GPPs), making it possible
to build an entire network while only spending money on the hardware
itself - computers and Radio-Frequency (RF) front-ends. After comparison
and analysis of several open-source LTE SDR platforms, the EURECOM's
OpenAirInterface (OAI) was chosen, providing a 3GPP standard-compliant
implementation of Release 8.6 (with a subset of Release 10 functionalities).
The main goal of this dissertation is the implementation of a
exible opensource
LTE User Equipment (UE) software radio platform on a compact
and low-power Single Board Computer (SBC) device, integrated with an
RF hardware front-end - Universal Software Radio Peripheral (USRP). It
supports real-time Time Division Duplex (TDD) and Frequency Division
Duplex (FDD) LTE modes and the recon guration of several parameters,
namely the carrier frequency, bandwidth and the number of LTE Resource
Blocks (RB) used. It can also share its LTE mobile data with nearby users,
similarly to a Wi-Fi hotspot. The implementation is described through
its several developing steps, including the porting of the UE from a regular
computer to a SBC. The performance of the network is then analysed based
on measured results of throughput
Cooperative control of relay based cellular networks
PhDThe increasing popularity of wireless communications and the higher data
requirements of new types of service lead to higher demands on wireless networks.
Relay based cellular networks have been seen as an effective way to meet users’
increased data rate requirements while still retaining the benefits of a cellular
structure. However, maximizing the probability of providing service and spectrum
efficiency are still major challenges for network operators and engineers because of
the heterogeneous traffic demands, hard-to-predict user movements and complex
traffic models.
In a mobile network, load balancing is recognised as an efficient way to increase
the utilization of limited frequency spectrum at reasonable costs. Cooperative
control based on geographic load balancing is employed to provide flexibility for
relay based cellular networks and to respond to changes in the environment.
According to the potential capability of existing antenna systems, adaptive radio
frequency domain control in the physical layer is explored to provide coverage at
the right place at the right time.
This thesis proposes several effective and efficient approaches to improve
spectrum efficiency using network wide optimization to coordinate the coverage
offered by different network components according to the antenna models and
relay station capability. The approaches include tilting of antenna sectors,
changing the power of omni-directional antennas, and changing the assignment of
relay stations to different base stations. Experiments show that the proposed
approaches offer significant improvements and robustness in heterogeneous traffic
scenarios and when the propagation environment changes. The issue of predicting
the consequence of cooperative decisions regarding antenna configurations when
applied in a realistic environment is described, and a coverage prediction model is
proposed. The consequences of applying changes to the antenna configuration on
handovers are analysed in detail. The performance evaluations are based on a
system level simulator in the context of Mobile WiMAX technology, but the
concepts apply more generally
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