Application of Space-Time Diversity/Coding For Power Line Channels

The purpose of the present work is to evaluate the application of space-time block codes to the transmission of digital data over the power-line communication channel (PLC). Data transmitted over the power-line channel is usually corrupted by impulsive noise. In this work we analyse the performance of space-time block codes in this type of environment and show that a significant performance gain can be achieved at almost no processing expense

EM based channel estimation in an amplify-and-forward relaying network

Cooperative communication offers a way to obtain spatial diversity in a wireless network without increasing hardware demands. The different cooperation protocols proposed in the literature [1] are often studied under the assumption that all channel state information is available at the destination. In a practical scenario, channel estimates need to be derived from the broadcasted signals. In this paper, we study the Amplify-and-Forward protocol and use the expectation-maximization (EM) algorithm to obtain the channel estimates in an iterative way. Our results show that the performance of the system that knows the channels can be approached at the cost of an increased computational complexity. In case a small constellation is used, a low complexity approximation is proposed with a similar performance

EM based channel estimation in an amplify-and-forward relaying network

Cooperative communication offers a way to obtain spatial diversity in a wireless network without increasing hardware demands. The different cooperation protocols proposed in the literature [1] are often studied under the assumption that all channel state information is available at the destination. In a practical scenario, channel estimates need to be derived from the broadcasted signals. In this paper, we study the Amplify-and-Forward protocol and use the expectation-maximization (EM) algorithm to obtain the channel estimates in an iterative way. Our results show that the performance of the system that knows the channels can be approached at the cost of an increased computational complexity. In case a small constellation is used, a low complexity approximation is proposed with a similar performance

A REVIEW ON SPACE TIME CODING

The invention of the radio telegraph by Marconi more than hundred years ago was the begining of wireless communications. In the last few decades , the rapid progress in radio technology has activated a communications revolution. Wireless systems have undergone through the world to help people and machines to communicate with each other independent of their location. This is a review paper on space time c oding. We have done the study analysis of different space time code, its mathematical analysis with the help of equations.We have discussed here two new stbc which are respectively STBC and Qo - STBC

Multi-user MIMO antenna systems using semi-orthogonal space division multiplexing and single-user QR-triangular detection

Orthogonal space division multiplexing (OSDM) can be achieved by utilizing multiple antennas at the base station (BS) and all mobile stations (MS) (or multi-user MIMO) jointly. Recently in [1, 2], two iterative methods have been proposed to obtain the antenna weighting for realizing OSDM in the downlink. However, both suffer from high complexity if the number of BS antennas or users involved is large, as the computational complexity grows with the number of users to the fourth power. In this paper, by allowing the signal streams for a user to be non-orthogonal, we propose a semi-OSDM system for complexity reduction. In the proposed semi-OSDM system, the signals of multiple users are still orthogonal, but for each user, the multiple signaling streams are made triangular instead so that a simple backward substitution with symbol cancellation can be performed to maintain an accurate signal detection. Remarkably, the antenna weighting for semi-OSDM can be expressed in a closed form. Simulation results show that semi-OSDM has mild performance degradation, but it requires much lower computational complexity (by an order of magnitude) when compared with existing OSDM systems.published_or_final_versio

Adaptive transmit eigenbeamforming with orthogonal space-time block coding in correlated space-time channels

Conventional space-time codes can provide a significant improvement in system performance only if the signal paths are spatially uncorrelated, a condition that is hardly met in practice. In this paper, we mitigate this condition by combining a technique of eigenbeamforming, based on the channel correlation matrix, with orthogonal space-time block codes (O-STBC) at the transmitter side of the link. No feedback information from the receiver (the mobile station) is utilized in the proposed structure. Simulation results using 4-ary PSK signaling showed that this idea outperforms existing techniques in both uncorrelated and correlated channels in terms of bit-error rate and symbol-error rate