Title: Cognitive Radio for Asymmetric Cellular Downlink with Multi-User MIMO Show Chinese title

Title: 认知无线电用于非对称蜂窝下行链路的多用户MIMO

Abstract: Cognitive radio (CR) is an important technique for improving spectral efficiency, letting a secondary system operate in a wireless spectrum when the primary system does not make use of it. While it has been widely explored over the past 25 years, many common assumptions are not aligned with the realities of 5G networks. In this paper, we consider the CR problem for the following setup: (i) infrastructure-based systems, where downlink transmissions might occur to receivers whose positions are not, or not exactly, known; (ii) multi-beam antennas at both primary and secondary base stations. We formulate a detailed protocol to determine when secondary transmissions into different beam directions can interfere with primary users at potential locations and create probability-based interference rules. We then analyze the "catastrophic interference" probability and the "missed transmission opportunity" probability, as well as the achievable throughput, as a function of the transmit powers of the primary and secondary base stations and the sensing window of the secondary base station. Results can serve to more realistically assess the spectral efficiency gains in 5G infrastructure-based cognitive systems. Show Chinese abstract

Abstract: 认知无线电（CR）是一种提高频谱效率的重要技术，它允许次要系统在主要系统未使用无线频谱时进行操作。 尽管在过去25年中已广泛研究，但许多常见的假设与5G网络的实际情况并不一致。 在本文中，我们考虑以下设置下的CR问题：（i）基于基础设施的系统，其中下行传输可能发送到位置未知或不完全已知的接收器；（ii）主基站和次基站均配备多波束天线。 我们制定了一种详细的协议，以确定次级传输进入不同波束方向时，可能在潜在位置干扰主用户，并生成基于概率的干扰规则。 然后，我们分析了“灾难性干扰”概率和“遗漏传输机会”概率，以及作为主基站和次基站发射功率以及次基站感知窗口函数的可实现吞吐量。 结果可用于更现实地评估5G基于基础设施的认知系统的频谱效率增益。