458 research outputs found
Robust transceiver designs for MIMO relay communication systems
The thesis investigates robust linear and non-linear transceiver design problems for wireless MIMO relay communication systems with the assumption that the partial information of the channel is available at the relay node. The joint source and relay optimization problems for MIMO relay systems are highly nonconvex, in general. We transform the problems into suitable forms which can be efficiently solved using standard convex optimization techniques. The proposed design schemes outperform the existing techniques
Channel Covariance Information Based Transceiver Design for AF MIMO Relay Systems with Direct Link
In this paper, we propose a design scheme for amplify-and-forward multiple-input multiple-output (AF MIMO) relay system with direct link to minimize the mean-squared error (MSE) of the signal estimation at the destination. In the proposed design scheme, an optimal precoding matrix is derived with the assumption that the full channel state information (CSI) of the source-relay link and partial channel state information such as channel covariance information (CCI) of the relay-destination link are available at the relay. In practical cases, if the destination is closer to the source, the source-destination link cannot be ignored. Hence, in this paper, we assume that the relay knows the partial channel state information of the source-destination link. Based on this assumption, an iterative optimal covariance algorithm is developed to achieve the minimum MSE of the signal estimation at the destination. In order to reduce computational complexity of the proposed optimal covariance algorithm, a suboptimal covariance algorithm is proposed. A numerical example shows that the developed optimal covariance algorithm outperforms the conventional CCI based MSE algorithms
End-to-End Joint Antenna Selection Strategy and Distributed Compress and Forward Strategy for Relay Channels
Multi-hop relay channels use multiple relay stages, each with multiple relay
nodes, to facilitate communication between a source and destination.
Previously, distributed space-time codes were proposed to maximize the
achievable diversity-multiplexing tradeoff, however, they fail to achieve all
the points of the optimal diversity-multiplexing tradeoff. In the presence of a
low-rate feedback link from the destination to each relay stage and the source,
this paper proposes an end-to-end antenna selection (EEAS) strategy as an
alternative to distributed space-time codes. The EEAS strategy uses a subset of
antennas of each relay stage for transmission of the source signal to the
destination with amplify and forwarding at each relay stage. The subsets are
chosen such that they maximize the end-to-end mutual information at the
destination. The EEAS strategy achieves the corner points of the optimal
diversity-multiplexing tradeoff (corresponding to maximum diversity gain and
maximum multiplexing gain) and achieves better diversity gain at intermediate
values of multiplexing gain, versus the best known distributed space-time
coding strategies. A distributed compress and forward (CF) strategy is also
proposed to achieve all points of the optimal diversity-multiplexing tradeoff
for a two-hop relay channel with multiple relay nodes.Comment: Accepted for publication in the special issue on cooperative
communication in the Eurasip Journal on Wireless Communication and Networkin
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