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arXiv · 1807.10619

Power Minimizer Symbol-Level Precoding: A Closed-Form Sub-Optimal Solution

A. Haqiqatnejad·F. Kayhan·B. Ottersten
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Abstract

In this letter, we study the optimal solution of the multiuser symbol-level precoding (SLP) for minimization of the total transmit power under given signal-to-interference-plus-noise ratio (SINR) constraints. Adopting the distance preserving constructive interference regions (DPCIR), we first derive a simplified reformulation of the problem. Then, we analyze the structure of the optimal solution using the Karush-Kuhn-Tucker (KKT) optimality conditions, thereby we obtain the necessary and sufficient condition under which the power minimizer SLP is equivalent to the conventional zero-forcing beamforming (ZFBF). This further leads us to a closed-form sub-optimal SLP solution (CF-SLP) for the original problem. Simulation results show that CF-SLP provides significant gains over ZFBF, while performing quite close to the optimal SLP in scenarios with rather small number of users. The results further indicate that the CF-SLP method has a reduction of order $10^3$ in computational time compared to the optimal solution.

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A. Haqiqatnejad, F. Kayhan, B. Ottersten. 2018-07-27. Power Minimizer Symbol-Level Precoding: A Closed-Form Sub-Optimal Solution. https://arxiv.org/abs/1807.10619

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