The new radio (NR) system is recently proposed to deploy alongside the long term evolution (LTE) system to improve the wireless communication capacity. The Vandermonde-subspace frequency division multiplexing (VFDM) is an efficient technique for such a two tier network, whereby the NR transmitter can reuse the frequency spectrum of LTE system meanwhile guaranteeing interference free to LTE. In this paper, we first investigate the robust rate-maximization problem in the VFDM system. In the condition of imperfect channel state information (CSI), the precoder is optimized to satisfy both non-interference to LTE system and rate-maximization in the NR system. To tackle the challenge in solving such a non-convex problem, an iterative algorithm is proposed based on the block coordinate descent (BCD) and penalty dual decomposition (PDD) methods. Finally, simulation results demonstrate the superiority of the proposed algorithm in terms of robustness and achievable rate over the conventional SVD-based VFDM technique.

中文翻译：

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VFDM系统的鲁棒速率最大化预编码器设计

最近提议将新的无线电 (NR) 系统与长期演进 (LTE) 系统一起部署，以提高无线通信容量。Vandermonde-子空间频分复用（VFDM）是这种两层网络的有效技术，NR发射机可以借此复用LTE系统的频谱，同时保证对LTE无干扰。在本文中，我们首先研究了 VFDM 系统中的鲁棒率最大化问题。在信道状态信息(CSI)不完善的情况下，预编码器被优化以满足对LTE系统的不干扰和NR系统中的速率最大化。为了解决解决此类非凸问题的挑战，提出了一种基于块坐标下降（BCD）和惩罚对偶分解（PDD）方法的迭代算法。最后，