标题： 不当的信令和符号扩展：在干扰的MAC中，使用高斯点对点码本能走多远？ 显示英文标题

标题： Improper signaling and symbol extensions: How far can we go with Gaussian P2P codebooks in the interfering MAC with TIN?

摘要： 满足5G的挑战需要通过允许多个方共享资源来更好地利用可用频谱。 例如，次级非授权系统可以与主授权系统的蜂窝上行链路共享资源，以提高频谱效率。 这会引入干扰，在设计此类系统时必须考虑这种干扰。 一种简单而稳健的策略是将干扰视为噪声（TIN），这在实践中被广泛采用。 因此，研究TIN在这些情况下的能力和限制是很重要的。 在本文中，我们研究了这种场景，该场景被建模为由点对点（P2P）信道干扰的多址接入信道（MAC）。 在这里，我们分别关注速率最大化和功率最小化问题。 我们在发射机上使用非正规高斯信号（而不是正规信号）以增加设计灵活性，这提供了除了优化发送信号方差之外，优化发送信号伪方差的自由度。 此外，为了在扩展信道上进行最优信号设计，我们允许在正交资源基底（即时间或频率）上的发送信号之间存在相关性。 我们将速率最大化问题公式化为半定规划，并使用半定松弛（SDR）来获得一个近似最优解。 数值优化显示，通过非正规高斯信号，可实现的速率可以根据干扰链路的强度提高多达三倍。 此外，与传统的正规高斯信号相比，通过符号扩展的非正规高斯信号在功率消耗方面表现出显著的优势。 有趣的是，给定速率最大化问题的解来最小化总功率可以显著提高能量效率。 显示英文摘要

摘要： Meeting the challenges of 5G demands better exploitation of the available spectrum by allowing multiple parties to share resources. For instance, a secondary unlicensed system can share resources with the cellular uplink of a primary licensed system for an improved spectral efficiency. This induces interference which has to be taken into account when designing such a system. A simple yet robust strategy is treating interference as noise (TIN), which is widely adapted in practice. It is thus important to study the capabilities and limitations of TIN in such scenarios. In this paper, we study this scenario modelled as Multiple Access Channel (MAC) interfered by a Point-to-Point (P2P) channel. Here, we focus on rate maximization and power minimization problems separately. We use improper Gaussian signaling (instead of proper) at the transmitters to increase the design flexibility, which offers the freedom of optimizing the transmit signal pseudo-variance in addition to its variance. Furthermore, we allow correlation among the transmitted signals over orthogonal resource basis (i.e., time or frequency) for the purpose of optimal signaling design over the extended channel. We formulate the rate maximization problem as a semidefinite program, and use semidefinite relaxation (SDR) to obtain a near-optimal solution. Numerical optimizations show that, by improper Gaussian signaling the achievable rates can be improved upto three times depending on the strength of the interfering links. Furthermore, we observe significant benefits in power consumption by improper Gaussian signaling with symbol extensions compared to the traditional proper Gaussian signaling. Interestingly, by minimizing sum power given the solution of the rate maximization problem improves the energy efficiency significantly.