Space Time Block Coding and MIMO Channels:Performance Results

IJMER

Space–time block coding is used for data communication in fading channels by multiple transmit antennas. Message data is encoded by applying a space–time block code and after the encoding the data is break into ‘n’ streams of simultaneously transmitted strings through n transmit antennas. The received signal at the receiver end is the superposition of the n transmitted signals distorted due to noise .For data recovery maximum likelihood decoding scheme is applied through decoupling of the signals transmitted from different antennas instead of joint detection. The maximum likelihood decoding scheme applies the orthogonal structure of the space–time block code (OSTBC) and gives a maximum-likelihood decoding algorithm based on linear processing at the receiver. In this paper orthogonal space–time block codes based model is developed using Matlab/Simulink to get the maximum diversity order for a given number of transmit and receive antennas subject with a simple decoding algorithm. The simulink block of orthogonal space coding block with space–time block codes is applied with and without gray coding. The OSTBC codes gives the maximum possible transmission rate for any number of transmit antennas using any arbitrary real constellation such of M-PSK array. For different complex constellation of M- PSK space–time block codes are applied that achieve 1/2 and 3/4 of the maximum possible transmission rate for MIMO transmit antennas using different complex constellations.

International Journal of Engineering Sciences & Research Technology, 2014

ISpace time block codes are the orthogonal codes design with an objective to reduce the interference in the fading environment.In mimo systems where there are multiple antenna at the transmitter side there will be a high probability of interference amongst the signal when all the users transmit the data simultaneously thus space time block codes provide an effective solution in such scenario with its orthogonal structure design which minimises the interference and thus make the receiver to easily demodulate the incoming arriving signal at the respective receiving antenna and thus detection of signal at the receiver will become quite simple with much reduced complexity.In this research paper various equalization techniques at transmitter and receiver are presented which aims to reduce the ISI ,other source nterferences and thus reduce BER(bit error rate)which is a measure of performance of various communicating system The organization of paper is as follows section1introduces the reader to space time block codes.section 2 give an overview of channel models .section3 provides space time block coding with different schemes,section 4 represents system models.section 5 depicts different diversity techniques to combat fading.section 6 provide an insight of equlization techniques at transmitter .section 7 famialarize with equalization techniques at the receiver transmitter. Simulation results shows ber analysis of defferent techniques and confirm sphere decoder is an optimum decoder with much reduced complexity

2015

Data is encoded using a space–time block code and the encoded data is split into n streams which are simultaneously transmitted using n transmit antennas. The received signal at each receive antenna is a linear superposition of the n transmitted signals perturbed by noise. The wireless systems that is evolved the last few decades necessitates in the design and analysis of equalization techniques. Future generation of wireless system is supposed to possess very high spectral efficiency. When data is transmitted at high rates over mobile radio channels, impulse response can extend over many symbol periods which lead to Inter Symbol Interference. Space– time block codes [STBC] are designed to achieve the maximum diversity order for a given number of transmit and receive antennas subject to the constraint of having a simple decoding algorithm. In this paper, we present the performance analysis of Alamouti STBC and MIMO Equalization. Compare MIMO -STBC with SISO, MRC and 2x1 and 2x2 Alam...

2013

Multiple-input and multiple-output, or MIMO, is the use of multiple antennas at both the transmitter and receiver to improve communication performance. MIMO technology has attracted attention in wireless communications, because it offers significant increases in data throughput and link range without additional bandwidth or transmit power. In this paper, multiple-input–multiple-output (MIMO) systems with reduced complexity is considered. The space–time block coding, for communication over Rayleigh fading channels using multiple transmit antennas is considered. Also the Alamouti code is tested for the performance. Data is encoded using a space–time block code and the encoded data is split into n streams which are simultaneously transmitted using n transmit antennas. The received signal at each receive antenna is a linear superposition of the n transmitted signals perturbed by noise. In current research, high data rate wireless communications, transmission rates, is of major interest....

2015

Multi Input Multi Output (MIMO) communication is a proven technique to increase the throughput, diversity gain and increase the energy gain by reducing the energy consumption of the wireless network. Space time diversity used in MIMO systems is a technique to mitigate multipath fading. The same information is transmitted over multiple channels that fade independently. So, space time diversity is achieved. Transmit space time diversity is achieved if the transmitter has knowledge of the channel. But, if the transmitter does not know the channel then it is necessary to code across both space and time to achieve diversity which is termed as space time coding. In this article, we discuss the developments in MIMO systems and Space Time Block Coding Techniques for MIMO systems, over the years.

Conference Record of the Thirty-Sixth Asilomar Conference on Signals, Systems and Computers, 2002.

The performance of space-time block codes for transmission over Quasi-static Rayleigh flat fading channels using multiple transmit antennas is considered. Data is prearranged using a space-time block code, which is split in to parallel streams via simultaneously transmitted transmit antennas. The received signal at each receive antenna is a linear superposition of the n transmitted signals perturbed by noise. Maximum likelihood decoding is carried out by dividing the signals transmitted from different antennas. This uses the orthogonal structure of the space-time block code and gives a maximum-likelihood decoding algorithm, which is based only on linear processing at the receiver. The performance of Space Time Block Codes for 1 bit/sec/HZ and 2 bits/sec/HZ using BPSK,QPSK Modulation Schemes for four and eight transmit antennas with code rate of 1/2 and 4/7 is evaluated. By increasing the code rate of the system using four transmit antennas, significant gains are achieved compared to existing system.

2017

Abstract: The Space Time Coding has proven to be an evolved research area in wireless communications. Recently, Space-Time Block Coding (STBC) has been trying to incorporate in the forthcoming generation of mobile communication standard with aims to deliver true media capability. This paper presents the Space-Time Block Codes (STBC) for wireless networks that uses multiple number of antennas at both transmitter and receiver to transmit and receive data over various channels (Rayleigh and Rician). The simulations have been done in SIMULINK. Different modulation schemes (DPSK and BPSK) have been adopted to check the performance of the system via Bit Error Rate Vs Signal to Noise Ratio.

International Journal of Advanced Research in Electrical, Electronics and Instrumentation Energy, 2013

In this paper analytic and experimental result on space-time block codes (STBCs) of various diversity orders including an assessment of its result by means of computer simulation are illustrated. STBCs originally introduced by Alamouti, have evolved as a revolution coding scheme in modern wireless communication field. Here, after presenting a general overview of MIMO systems, we will compare the performance results of STB codes of various diversity orders through computer simulations. Then we will determine the optimum diversity order of STB codes for the MIMO systems.

IEEE Transactions on Wireless Communications, 2000

In this letter, we present a unified mathematical expression for the decoding algorithm of space-time block codes (STBC). Based on the unified expression, we make a comparison of the STBC transmit diversity and the maximal-ratio combining MRC receive diversity, and analyze the symbol error probability for the STBC transmissions. The effects of the channel correlation and the number of transmit and receive antennas on the performance of the STBC are discussed.

Wireless networks have quickly become part of everyday life. Wireless LANs, cell phone networks, and personal area networks are just a few examples of widely used wireless networks. However, wireless devices are range and data rate limited. The research community has spent a great deal of effort on finding ways to overcome these limitations. One method is to use Multiple-Input Multiple-Output (MIMO) links. The multiple antennas allow MIMO systems to perform precoding (multi-layer beamforming), diversity coding (space-time coding), and spatial multiplexing. Beamforming consists of transmitting the same signal with different gain and phase (called wights) over all transmit antennas such that the receiver signal is maximized. Diversity consists of transmitting a single space-time coded stream through all antennas. Spatial multiplexing increases network capacity by splitting a high rate signal into multiple lower rate streams and transmitting them through the different antennas. In spatial multiplexing, the receiver can successfully decode each stream given that the received signals have sufficient spatial signatures and that the receiver has enough antennas to separate the streams. The result of using these MIMO techniques is higher data rate or longer transmit range without requiring additional bandwidth or transmit power. This paper presents a detailed study of diversity coding for MIMO systems. Different space-time block coding (STBC) schemes including Alamouti's STBC for 2 transmit antennas as well as orthogonal STBC for 3 and 4 transmit antennas are explored. Finally, these STBC techniques are implemented in MATLAB and analyzed for performance according to their bit-error rates using BPSK, QPSK, 16-QAM, and 64-QAM modulation schemes.