MIMO

Downlink MIMO For the downlink MIMO system configurations with two or four antennas has being considered. In 2x2 configurations there is baseline configuration with two antennas at the transmitter and two antennas at the receiver. There are different modes has been predicted for MIMO antenna system such as spatial multiplexing and transmit diversity and channel automatically select any scheme of choice. Spatial multiplexing In spatial multiplexing scheme the different stream of data has been transmitted

There is a number of different MIMO configurations or formats that can be used. These are termed SISO, SIMO, MISO and MIMO. These different MIMO formats offer different advantages and disadvantages - these can be balanced to provide the optimum solution for any given application. The different MIMO formats - SISO, SIMO, MISO and MIMO require different numbers of antennas as well as having different levels of complexity. Also dependent upon the format, processing may be needed at one end of the link

MIMO techniques are mostly used to accelerate system throughput over disruptive wireless communication channels. It is well known fact that with the number of transmit antenna M and number of receive antenna N, the capacity of MIMO systems increases linearly with a factor of MN. The receiver decodes the received signal vectors into actual information, a narrow band flat fading MIMO is designed as: Y=Hx+n ------ (1) Where Y & x are received and transmitted vectors, H is channel matrix

Space time coding techniques for MIMO-OFDM OFDM provides the frequency selective channel which can able to divides the frequency band into multiple sub channels and each sub channel carries a different stream of symbols. There is flat frequency response throughput each sub channel when there is narrow bandwidth of each sub channel. Therefore OFDM able to transform a frequency selective channel into set of multiple flat-fading channels. Simultaneously when M transmit antennas used an OFDM transmitter

the shoulders of giants, Teletarand Foschinigave the technique of MIMO system which would increase the spectral efficiency of the wireless system to its maximum compared to all the current technologies. Multiple antennas are used for transmission and reception to increases the capacity of the wireless channel.Capacity is expressed as the

Error Performance improvement in Spatially Multiplexed MIMO Systems over Weibull-Gamma Fading Channel Keerti Tiwari and Davinder S. Saini Department of Electronics and Communication Engineering Jaypee University of Information Technology Waknaghat, Solan, (H.P.) - 173234, India E-mail- keerti.tiwari@mail.juit.ac.in, davinder.saini@juit.ac.in Abstract- In multiple-input multiple-output (MIMO) systems, spatial demultiplexing at the receiver is a motivational task. Thus, several detection techniques

relays was proposed in [10] to minimize the energy consumption of each data packet. In a tutorial article [11], some energy efficient approaches of MIMO techniques for the enhanced IEEE 802.11a communications without using any relays have been reviewed. A randomized scheduling policy is proposed to pursue the high energy efficiency in the point-to-point MIMO downlink channels using the singular value decomposition technique [12], which is then extended to multi-user systems in [13]. For single-relay

INPUT MULTIPLE OUTPUT (MIMO) In MIMO system there is multiple antennas is provided at the transmitter side as well as receiver side. Using multiple antennas at the transmitter and the receiver side could able to increase spectral efficiency, produces higher capacity and provides more data rates for wireless communication. In MIMO system there is SU-MIMO that is called single user MIMO in which when there is data rates need to be increased for single user then it is known as SU-MIMO, and if there is individual

Further the consideration of space domain either with space diversity, smart antennas, and nowadays, MIMO systems has also pushed the evolution of propagation modeling toward more complex spatio-temporal considerations [1]. The MIMO antenna for wireless communications is required to have a multiple bandwidth to cover the GSM, and ISM bands. On the other hand, it is said that about 70% of the user demands and

This diversity gain provides reliable and energy efficient transmission. Virtual MIMO When multiple single user antennas share their antennas to create virtual antenna array, then virtual MIMO is developed. This is possible because of Distributed Space Time Block Codes (DSTBCs). The following figure shows the system model of the virtual MIMO. A. Simple Relay Selection Algorithm In the simple relay algorithm, a set of nodes is assigned random positions in the