Browsing by Author "Tsao, Hen-Wai"

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Development of 400 Gb/s optical transceivers for SMF based datacenter optical interconnect
(2018-01-01)
Lee, San-Liang
;
Chen, Jyehong
;
Liu, Shen-Iuan
;
Yang, Chang-Fa
;
Tsao, Hen-Wai
We reported the progress of developing 400-Gb/s optical transceivers with 1.3-mu m electro-absorption modulators for optical interconnect applications in data centers. The key technologies include high-speed light sources, silicon photonics based WDM multiplexers/de-multiplexers, driving and receiving circuits, signal processing and monitoring schemes.
Distributed Beamforming with Improper Gaussian Signaling for MIMO Interference Broadcast Channels
(2017-01-01)
Lin, Jhe-Yi
;
Chang, Ronald Y.
;
Lee, Chia-Han
;
Tsao, Hen-Wai
;
電機工程學系
For rate optimization in interference limited network, improper Gaussian signaling has shown its capability to outperform the conventional proper Gaussian signaling. In this work, we study a weighted sum rate maximization problem with improper Gaussian signaling for the multiple-input multiple-output interference broadcast channel (MIMO-IBC). To solve this nonconvex and NP-hard problem, we propose an effective two-stage algorithm. In the first stage, a weighted mean square error (MSE) minimization algorithm is adopted to compute the transmit covariance matrices, and in the second stage, an alternating direction method of multipliers (ADMM)-based distributed multi-agent algorithm is proposed to obtain the globally optimal pseudo-covariance matrices in a parallel and scalable fashion. Finally, simulation results are presented to demonstrate the superior performance of our algorithm under different signal-to-noise ratio (SNR) and various network scenarios.
Multi-Agent Distributed Beamforming With Improper Gaussian Signaling for MIMO Interference Broadcast Channels
(2019-01-01)
Lin, Jhe-Yi
;
Chang, Ronald Y.
;
Lee, Chia-Han
;
Tsao, Hen-Wai
;
Su, Hsuan-Jung
For rate optimization in interference limited networks, improper Gaussian signaling has shown its ability to outperform conventional proper Gaussian signaling. In this paper, we study a weighted sum-rate maximization problem with improper Gaussian signaling for the multiple-input multiple-output interference broadcast channel. To solve this nonconvex and NP-hard problem, we propose an effective separate covariance and pseudo-covariance matrices optimization algorithm. In the covariance optimization, a weighted minimum mean square error algorithm is adopted, and in the pseudo-covariance optimization, an alternating optimization (AO) algorithm is proposed, which guarantees convergence to a stationary solution and ensures a sum-rate improvement over proper Gaussian signaling. An alternating direction method of multipliers-based multi-agent distributed algorithm is proposed to solve an AO subproblem with the globally optimal solution in a parallel and scalable fashion. The proposed scheme exhibits favorable convergence, optimality, and complexity properties for future large-scale networks. The simulation results demonstrate the superior sum-rate performance of the proposed algorithm as compared with the existing schemes with proper as well as improper Gaussian signaling under various network configurations.