The demand of different multimedia services and different internet supported applications on mobile devices requires a high speed data rate and good service of quality. This can be obtained by implementing multiple Antenna technology on both stations i.e. User terminal and base station with an appropriate coding technique, and on the other hand MIMO can fulfill 3G & 4G demand and standard with a combination of other techniques. The system's error performance is analyzed through simulation which showed the simulated results of Multi-Rate Resource Control (MRRC) scheme and Alamouti scheme are identical. And also the Bit Error Rate (BER) were checked for different MIMO systems. By improving the BER, we will get the better QoS.
MIMO-OFDM for LTE, WIFI and WIMAX: Coherent versus Non-Coherent and Cooperative Turbo-Transceivers provides an up-to-date portrayal of wireless transmission based on OFDM techniques augmented with Space-Time Block Codes (STBCs) and Spatial-Division Multiple Access (SDMA). The volume also offers an in-depth treatment of cutting-edge Cooperative Communications. This monograph collates the latest techniques in a number of specific design areas of turbo-detected MIMO-OFDM wireless systems. As a result a wide range of topical subjects are examined, including channel coding and multiuser detection (MUD), with a special emphasis on optimum maximum-likelihood (ML) MUDs, reduced-complexity genetic algorithm aided near-ML MUDs and sphere detection. The benefits of spreading codes as well as joint iterative channel and data estimation are only a few of the radical new features of the book. Also considered are the benefits of turbo and LDPC channel coding, the entire suite of known joint coding and modulation schemes, space-time coding as well as SDM/SDMA MIMOs within the context of various application examples. The book systematically converts the lessons of Shannon's information theory into design principles applicable to practical wireless systems; the depth of discussions increases towards the end of the book. Discusses many state-of-the-art topics important to today's wireless communications engineers. Includes numerous complete system design examples for the industrial practitioner. Offers a detailed portrayal of sphere detection. Based on over twenty years of research into OFDM in the context of various applications, subsequently presenting comprehensive bibliographies.
MIMO-OFDM for LTE, WIFI and WIMAX: Coherent versus Non-Coherent and Cooperative Turbo-Transceivers provides an up-to-date portrayal of wireless transmission based on OFDM techniques augmented with Space-Time Block Codes (STBCs) and Spatial-Division Multiple Access (SDMA). The volume also offers an in-depth treatment of cutting-edge Cooperative Communications. This monograph collates the latest techniques in a number of specific design areas of turbo-detected MIMO-OFDM wireless systems. As a result a wide range of topical subjects are examined, including channel coding and multiuser detection (MUD), with a special emphasis on optimum maximum-likelihood (ML) MUDs, reduced-complexity genetic algorithm aided near-ML MUDs and sphere detection. The benefits of spreading codes as well as joint iterative channel and data estimation are only a few of the radical new features of the book. Also considered are the benefits of turbo and LDPC channel coding, the entire suite of known joint coding and modulation schemes, space-time coding as well as SDM/SDMA MIMOs within the context of various application examples. The book systematically converts the lessons of Shannon's information theory into design principles applicable to practical wireless systems; the depth of discussions increases towards the end of the book. Discusses many state-of-the-art topics important to today's wireless communications engineers. Includes numerous complete system design examples for the industrial practitioner. Offers a detailed portrayal of sphere detection. Based on over twenty years of research into OFDM in the context of various applications, subsequently presenting comprehensive bibliographies.
High spectral efficiency and high transmission data rate are the challenging requirements of wireless broadband communications. The MIMO technology has rapidly gained in popularity due to its powerful performance-enhancing capabilities. Spatial diversity can be obtained by using multiple antennas and space-time codes. For future wireless broadband systems, OFDM is discussed as access scheme. OFDM provides an essentially flat fading channel for each subcarrier by insertion of a cyclic guard interval at each antenna. Therefore, space-time block codes are well suited to be applied in OFDM. We investigate SFBC for OFDM systems with multiple transmit antennas, where coding is applied in the frequency domain rather than in the time domain. In this thesis, performance of two coding techniques STBC and SFBC is analyzed in OFDM. In order to appreciate the performances offered by coding through space and frequency, different simulation scenarios have been proposed where variation of the modulation order , channel fading, antenna selection technique, receiver diversity and effect of power conditions have been considered.
There are many technologies being considered for the next generation of wireless communications. Of these technologies, multi-input multi-output (MIMO), orthogonal frequency division multiplexing (OFDM) and Walsh spreading are drawing the most attention. Although a lot of research has been done in this area, it has not been decided yet as to which technology or combination of the technologies will be used in future wireless generations. The new generation will have to support high data rates and provide excellent performance in order to accommodate several multimedia services. In this thesis, a MIMO-OFDM system that employs Walsh sequences as block coding is designed. Simulation studies show that the proposed system exhibits high performance and comparisons show that it has low complexity compared to some of the previous systems. Two configurations are considered for the proposed system. The first configuration combines Vertical-Bell Labs Layered Space-Time (VBLAST), OFDM and Walsh block coding, for which a simplified implementation scheme for the proposed coding is presented. The system is investigated through extensive computer simulations using different system parameters and channel conditions. The proposed system is compared to some of the existing systems in terms of performance as well as computational complexity. The second configuration integrates space-time block coding (STBC), OFDM and Walsh block coding. In contrast to VBLAST, which aims to increase system capacity and data rates, STBC improves the system's performance through multipath diversity. The performance of the system is studied through computer simulations and the computational complexity of the system is also compared to some typical STBC systems from previous research. The simulations and comparisons of both configurations of the proposed system show its superiority in terms of performance and computational complexity to previous systems. Finally, to emulate real-life scenarios, the performance of the proposed system is also investigated using some common channel estimation techniques. It is shown that by utilizing a preamble of training symbols, the proposed system provides a satisfactory performance for both the configurations.
In this thesis the physical layer design of broadband MIMO-OFDM communication systems is considered taking into account the realistic multipath radio channel. The main focus is made on examining a number of coherent and non-coherent MIMO techniques both analytically and via computer simulations. Several proposals are made to assist intelligent selection of MIMO precoding and decoding algorithms. Additionally two novel improved differential transmission schemes are presented and analyzed. In dieser Arbeit wird der Entwurf der physikalischen Schicht für breitbandige MIMO-OFDM Kommunikationssysteme betrachtet. Dazu werden realistische Funkkanalmodelle mit Mehrwegeausbreitung berücksichtigt. Ein wesentlicher Schwerpunkt der Arbeit liegt auf Untersuchungen zu kohärenten und nichtkohärenten MIMO-Techniken, die sowohl analytisch als auch mit Hilfe von Computersimulationen durchgeführt werden. Es werden verschiedene Vorschläge erarbeitet, wie eine intelligente Auswahl von MIMO-Techniken zur Vorcodierung sowie zur Decodierung getroffen werden kann. Darüber hinaus werden zwei neuartige, verbesserte differentielle Übertragungsverfahren vorgestellt und analysiert.
The aim of this research work is to investigate error free transmission in wireless communications. In particular the thesis study MIMO multiplexing (spatial multiplexing) and diversity (space time coding) having OFDM modulation scheme. The report is based on the the fact that MIMO multiplexing increases a network capacity by splitting a high signal rate into multiple lower rate streams. It also fulfills the requirement by offering high data rate through spatial multiplexing gain and improved link reliability due to antenna diversity gain. Alamouti Space Time Block Code (STBC) scheme is used with orthogonal designs over multiple antennas which showed simulated results are identical to expected theoretical results. With this technique both Bit Error Rate (BER) and maximum diversity gain are achieved by increasing number of antennas on either side. This scheme is efficient in all the applications where system capacity is limited by multipath fading.
