217 research outputs found
Robust transceiver design for MIMO relay systems with tomlinson harashima precoding
In this paper we consider a robust transceiver design for two hop non-regenerative multiple-input multiple-output (MIMO) relay networks with imperfect channel state information (CSI). The transceiver consists of Tomlinson Harashima Pre-coding (THP) at the source with a linear precoder at the relay and linear equalisation at the destination. Under the assumption that each node in the network can acquire statistical knowledge of the channel in the form of a channel mean and estimation error covariance, we optimise the processors to minimise the expected arithmetic mean square error (MSE) subject to transmission power constraints at the source and relay. Simulation results demonstrate the robustness of the proposed transceiver design to channel estimation errors
Ordered Tomlinson-Harashima Precoding in G.fast Downstream
G.fast is an upcoming next generation DSL standard envisioned to use
bandwidth up to 212 MHz. Far-end crosstalk (FEXT) at these frequencies greatly
overcomes direct links. Its cancellation based on non-linear
Tomlinson-Harashima Precoding (THP) proved to show significant advantage over
standard linear precoding. This paper proposes a novel THP structure in which
ordering of successive interference pre-cancellation can be optimized for
downstream with non-cooperating receivers. The optimized scheme is compared to
existing THP structure denoted as equal-rate THP which is widely adopted in
wireless downlink. Structure and performance of both methods differ
significantly favoring the proposed scheme. The ordering that maximizes the
minimum rate (max-min fairness) for each tone of the discrete multi-tone
modulation is the familiar V-BLAST ordering. However, V-BLAST does not lead to
the global maximum when applied independently on each tone. The proposed novel
Dynamic Ordering (DO) strategy takes into account asymmetric channel statistics
to yield the highest minimum aggregated rate.Comment: 7 pages, 11 figures, Accepted at the 2015 IEEE Globecom 2015,
Selected Areas in Communications: Access Networks and Systems, 6-10 December,
201
Approximate minimum BER power allocation for MIMO-THP system
This paper proposes a transmit power allocation (TPA) scheme based on multiple-input multiple-output (MIMO) Tomlinson-Harashima precoding (THP) structure, where a TPA matrix is introduced to the conventional MIMO-THP. We analyze the influence of the introduced TPA matrix on the performance of MIMO-THP. The proposed TPA scheme invokes the minimum average uncoded bit-error rate (BER) criterion subjected to a sum-power constraint. During the derivation, we consider the effects of precoding loss factor on the TPA scheme and obtain a closed-form expression of the TPA. Compared to existing TPA methods for MIMO-THP systems, the proposed scheme reduces processing complexity and improves the BER performance
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