Handover Mechanism in NR for Ultra-Reliable Low-Latency Communications
Handover Mechanism in NR for Ultra-Reliable Low-Latency Communications
复制标题
DOI：
10.1109/mnet.2018.1700235
复制
发表时间：
2018-03-01
期刊：
影响因子：
9.3
通讯作者：
Lee, Jae-Yong
中科院分区：
文献类型：
--
作者：
Park, Hyun-Seo;Lee, Yuro;Lee, Jae-Yong
对于许多URLLC服务，移动性是一个关键的要求，以及延迟和可靠性。3GPP已经将MIT的目标定义为0 ms，并且对于5G，一般URLLC可靠性要求在1 ms的延迟内为1 - 10（-5）。在本文中，我们分析了MIT和切换失败（霍夫）率对可靠性性能的影响。根据分析，在120 km/h时，MIT为0 ms，实现1 - 10（-5）可靠性所需的霍夫率仅为0.52%。因此，为了实现URLLC的可靠性，我们不仅需要使MIT最小化，而且还需要使霍夫率尽可能接近于零。因此，我们提出了有条件的先接后断切换，同时以零MIT和零霍夫速率为目标。该解决方案可以通过直到来自目标小区的第一个或一些下行链路接收才释放到源小区的连接来实现零MIT。通过在到源小区的无线电链路仍然稳定时接收HO命令消息，并且通过在到目标小区的连接是优选的时执行切换，可以实现零霍夫速率。仿真结果表明，我们提出的解决方案可以实现几乎为零的霍夫率，即使在120公里/小时。
For many URLLC services, mobility is a key requirement together with latency and reliability. 3GPP has defined the target of MIT as 0 ms, and a general URLLC reliability requirement as 1 - 10(-5) within a latency of 1 ms for 5G. In this article, we analyzed the impact of MIT and handover failure (HOF) rate on the reliability performance. From the analysis, at 120 km/h, with MIT of 0 ms, the required HOF rate to achieve 1 - 10(-5) reliability is only 0.52 percent. Therefore, to achieve the reliability for URLLC, we need to minimize not only the MIT but also the HOF rate as close to zero as possible. Hence, we propose conditional make-before-break handover to target zero MIT and zero HOF rate simultaneously. The solution can achieve zero MIT by not releasing the connection to the source cell until the first or some downlink receptions from the target cell. It can achieve the zero HOF rate, by receiving an HO Command message when the radio link to the source cell is still stable, and by executing the handover when the connection to the target cell is preferable. Simulation results show that our proposed solution can achieve almost zero HOF rate even at 120 km/h.