System Level Simulation of E-MBMS Transmissions in LTE-A

Interference coordination methods for EvolvedMultimedia Broadcast/Multicast Service (E-MBMS) in LongTerm Evolution Advanced (LTE-A) are presented. In this paper, OFDM/OFDMA signals based on LTE parameters are combined with Multipoint MIMO, Turbo codes and signal space diversity methods. Different interference coordination techniques, such as, Multipoint MIMO coordination, Fixed Relay stations, adaptive frequency reuse and schedulers are considered to evaluate the E-MBMS spectral efficiency at the cell borders. The system level coverage and throughput gains of Multipoint MIMO system with hierarchical constellations and Turbo-codes are simulated associated to the presence or not of fixed relays and measuring the maximum spectral efficiencies at cell borders of single cell point-to-multipoint or single frequency network topologies. The influence of the relay transmission power and cell radius in the performance of the previous cellular topologies is also evaluated

Interference Coordination for E-MBMS Transmissions in LTE-Advanced

Interference coordination methods for Evolved-Multimedia Broadcast/Multicast Service (E-MBMS) in Long-Term Evolution Advanced (LTE-A) are presented. In addition, we consider signal space diversity based on Rotation Matrices (RM) known to provide good performance gains over uncorrelated Rayleigh fading channels. OFDM/OFDMA systems can make the use of RM very attractive both for single and multiple antenna transmissions. In this paper, OFDM/OFDMA signals based on LTE parameters are combined with RM, MIMO, Turbo, or LDPC codes. We have considered different types of receivers, namely, we used an MMSE (Minimum Mean Squared Error) equalizer and a Maximum Likelihood Soft Output criterion (MLSO). Frequency, signal, and space diversity gains are evaluated for different spatial channel models (SCM) based on ITU multipath propagation channels. Different adaptive frequency reuse and schedulers are considered to evaluate the E-MBMS spectral efficiency at the cell borders

Advanced transmitter and receivers in future wireless networks

O objectivo desta dissertação é aprofundar o estudo de tecnologias que permitam atingir comunicações mais eficientes e fiáveis nas futuras redes sem fios. Uma das tecnologias estudadas nesta dissertação e que ainda não existem muitos estudos é o Complex Rotation Matrix (CRM). Esta tecnologia é bastante útil em sistemas que usem multi-portadoras como o Orthogonal Frequency Division Multiplexing (OFDM) pois permite dividir a informação pelas várias sub-portadoras. Caso este sistema use também a tecnologia MIMO ainda permitirá a divisão da informação por várias antenas. As constelações hierárquicas são outro dos temas abordados nesta dissertação e são um método eficiente de entregar o mesmo conteúdo a diferentes utilizadores. Esta técnica poderá ser bastante útil tanto em sistemas de uma portadora como multi-portadoras. O Single Carrier (SC) é outra das tecnologias abordadas nesta dissertação. Um dos standards em que poderia ser utilizado tanto o OFDM com o SC é no Digital Video Broadcasting – Satellite services to Handhelds (DVB-SH). Este esquema de comunicação tem com propósito a entrega de conteúdos multimédia aos terminais móveis via comunicação com estações base ou por satélite. O uso de o OFDM no downlink (DL) e do SC no uplink (UL) no mesmo standard/protocolo teria repercussões também ao nível dos terminais móveis pois permitiria uma melhor eficiência na duração das baterias. Os resultados obtidos nesta tese visam sobretudo o estudo do CRM, estimação de canal e constelações hierárquicas. Para a obtenção de resultados foram efectuadas simulações com o método de Monte Carlo e Turbo Códigos. Os simuladores foram desenvolvidos em Matlab.The main purpose of this dissertation is the study of technologies that allow achieving more reliable and efficient communications in wireless systems. One of the technologies studied in this dissertation and practically new is the Complex Rotation Matrix (CRM). This technology is useful in systems that use multi-carrier as the Orthogonal Frequency Division Multiplexing (OFDM). The hierarchical constellations are other theme approached in this dissertation and it purpose efficiently is to deliver the same content to different users. Another technology studied in this dissertation was the Single Carrier (SC) with Frequency Division Equalization. The SC is a well-know technology and is used in several telecommunications systems. The goal is the future wireless communications adopt the two technologies in the same system and use one of them depending of the situation. The Digital Video Broadcasting – Satellite services to Handhelds (DVB-SH) is one standard that can take advantage of the using of the OFDM and SC in the same system. The main goal of the DVB-SH is deliver multimedia content via satellite communications or communications with base stations to mobile terminals. The mobile terminals can achieve a more efficiency in their batteries whether in a standard/protocol that uses OFDM in DL and SC in UL. The results obtained with this thesis have the purpose to study the CRM, channel estimation and hierarchical constellation. The simulators were developed in Matlab platform and Turbo Codes are the codification used, channel estimation is also used and all the simulations were made with the Monte Carlo method

Signal space cooperative communication with partial relay selection.

Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.Exploiting the available diversity from various sources in wireless networks is an easy way to improve performance at the expense of additional hardware, space, complexity and/or bandwidth. Signal space diversity (SSD) and cooperative communication are two promising techniques that exploit the available signal space and space diversity respectively. This study first presents symbol error rate (SER) analysis of an SSD system containing a single transmit antenna and N receive antennas with maximal-ratio combining (MRC) reception; thereafter it presents a simplified maximum-likelihood (ML) detection scheme for SSD systems, and finally presents the incorporation of SSD into a distributed switch and stay combining with partial relay selection (DSSC-PRS) system. Performance analysis of an SSD system containing a single transmit antenna and multiple receive antennas with MRC reception has been presented previously in the literature using the nearest neighbour (NN) approximation to the union bound, however results were not presented in closed form. Hence, closed form expressions are presented in this work. A new lower bound for the SER of an SSD system is also presented which is simpler to evaluate than the union bound/NN approximation and also simpler to use with other systems. The new lower bound is based on the minimum Euclidean distance of a rotated constellation and is termed the minimum distance lower bound (MDLB); it is also presented here in closed form. The presented bounds have been validated with simulation and found to be tight under certain conditions. The SSD scheme offers error performance and diversity benefits with the only penalty being an increase in detector complexity. Detection is performed in the ML sense and conventionally, all points in an M-ary quadrature amplitude modulation (M-QAM) constellation are searched to find the transmitted symbol. Hence, a simplified detection scheme is proposed that only searches m symbols from M after performing initial signal conditioning. The simplified detection scheme is able to provide SER performance close to that of optimal ML detection in systems with multiple receive antennas. Cooperative communication systems can benefit from the error performance and diversity gains of the spectrally efficient SSD scheme since it requires no additional hardware, bandwidth or transmit power. Integrating SSD into a DSSC-PRS system has shown an improvement of approximately 5dB at an SER of 10-4 with a slight decrease in spectral efficiency at low SNR. Analysis has been performed using the newly derived MDLB and confirmed with simulation