Existing minimum-mean-squared-error (MMSE) transceiver designs in amplified-and-forward (AF) multiple-input multiple-output (MIMO) two-way relay systems all assume a linear precoder at the sources. Non-linear source p...Existing minimum-mean-squared-error (MMSE) transceiver designs in amplified-and-forward (AF) multiple-input multiple-output (MIMO) two-way relay systems all assume a linear precoder at the sources. Non-linear source precoders in such a system have not been considered yet. In this paper, we study the joint design of source Tomlinson-Harashima precoders (THPs), relay linear precoder and MMSE receivers in two-way relay systems. This joint design problem is a highly nonconvex optimization problem. By dividing the original problem into three sub-problems, we propose an iterative algorithm to optimize precoders and receivers. The convergence of the algorithm is ensured since the updated solution is optimal to each sub-problem. Numerical simulation results show that the proposed iterative algorithm outperforms other algorithms in the high signal-to-noise ratio (SNR) region.展开更多
In multi-user multiple-input single-output orthogonal frequency-division multiplexing （MISO-OFDM） downlinks with limited feedback, both linear precoders （LP） and Tomlinson-Harashima precoders （THP） experience pe...In multi-user multiple-input single-output orthogonal frequency-division multiplexing （MISO-OFDM） downlinks with limited feedback, both linear precoders （LP） and Tomlinson-Harashima precoders （THP） experience performance degradation due to inaccurate channel state information at the transmitter （CSIT）. This analysis treats the downlink channels as random quantities and exploits their second order statistics in robust precoding schemes to correct the errors introduced in the feedback procedure. The time-domain channel vectors are found to reduce the feedback overhead more than the frequency-domain vectors. A compression and restoration method and a codebook design are also given to obtain compact feedback quantities. Simulations show that the robust LP and THP are superior to the previous methods with tradeoffs possible between performance and feedback overhead.展开更多
This paper proposes a joint nonlinear transceiver design scheme based on minimum mean square error （MMSE） criterion for non-regenerative multiple input multiple output （MIMO） relay system. The proposed scheme deco...This paper proposes a joint nonlinear transceiver design scheme based on minimum mean square error （MMSE） criterion for non-regenerative multiple input multiple output （MIMO） relay system. The proposed scheme decomposes the error covariance matrix, reformulates the original joint design problem as two separate optimization problems, and then provides a closed-form solution with only local channel state information （CSI） available at the source and destination. Performance evaluation shows that the proposed scheme significantly outperforms linear schemes, and has a competitive performance compared with existing global CSI based nonlinear schemes, both iterative and non-iterative.展开更多
基金the China National Science and Technology Major Project "New generation broadband wireless-mobile communication networks" (No. 2011ZX03001-002-01)
文摘Existing minimum-mean-squared-error (MMSE) transceiver designs in amplified-and-forward (AF) multiple-input multiple-output (MIMO) two-way relay systems all assume a linear precoder at the sources. Non-linear source precoders in such a system have not been considered yet. In this paper, we study the joint design of source Tomlinson-Harashima precoders (THPs), relay linear precoder and MMSE receivers in two-way relay systems. This joint design problem is a highly nonconvex optimization problem. By dividing the original problem into three sub-problems, we propose an iterative algorithm to optimize precoders and receivers. The convergence of the algorithm is ensured since the updated solution is optimal to each sub-problem. Numerical simulation results show that the proposed iterative algorithm outperforms other algorithms in the high signal-to-noise ratio (SNR) region.
基金Supported by the National Natural Science Foundation of China (No.60675002)
文摘In multi-user multiple-input single-output orthogonal frequency-division multiplexing （MISO-OFDM） downlinks with limited feedback, both linear precoders （LP） and Tomlinson-Harashima precoders （THP） experience performance degradation due to inaccurate channel state information at the transmitter （CSIT）. This analysis treats the downlink channels as random quantities and exploits their second order statistics in robust precoding schemes to correct the errors introduced in the feedback procedure. The time-domain channel vectors are found to reduce the feedback overhead more than the frequency-domain vectors. A compression and restoration method and a codebook design are also given to obtain compact feedback quantities. Simulations show that the robust LP and THP are superior to the previous methods with tradeoffs possible between performance and feedback overhead.
基金supported by National Basic Research Program of China (2009CB320401)the National Key Scientific and Technological Project of China (2010ZX03003-001,2012ZX03004005-002)the National Natural Science Foundation of China (61171100,61171099)
文摘This paper proposes a joint nonlinear transceiver design scheme based on minimum mean square error （MMSE） criterion for non-regenerative multiple input multiple output （MIMO） relay system. The proposed scheme decomposes the error covariance matrix, reformulates the original joint design problem as two separate optimization problems, and then provides a closed-form solution with only local channel state information （CSI） available at the source and destination. Performance evaluation shows that the proposed scheme significantly outperforms linear schemes, and has a competitive performance compared with existing global CSI based nonlinear schemes, both iterative and non-iterative.
