基于ORAN的RRU前传接口关键技术的实现与分析

Implementation and analysis of ORAN fronthaul technology in RRU

射频拉远单元(RRU)是位于接入网的远端设备,对接空中接口,因此对RRU的实时性要求较高。传统的接入架构是BBU与RRU相连,RRU负责处理中射频信号,基于ORAN的RRU增加了开放前传接口特性,能够保证性能同时兼容各个设备商的DU设备,达到体积小,能耗低,通用性强的目标。文章首先介绍了ORAN的架构和前传切分,然后介绍在RRU上实现Option7-2x的切分,并提出了一种在可编程门阵列中实现ORAN协议和LOWPHY的方案,最后比较了不同前传接口的优劣,通过比较得出ORAN架构的实现相对复杂,但降低了前传网络的占用带宽,在设备成本和通用性上有明显优势。

RRU is the remote equipment which is set up in access network, connected to air interface, therefore the real-time feature is significant. C-RAN architecture is based on the physical connection with BBU and RRU, the all new RRU with ORAN interface is more than a equipment that is only responsible for DFE, adding a feature of open interface, connecting to different brand of DU equipment. The ORAN ambition is to make equipment smaller, compatible, and low power consumption. This article introduces the architecture and the split of fronthaul, and then shows the implementation of Option7-2x in RRU based on FPGA, ORAN and LOWPHY module are designed in it, at last we compared pros and cons of different splits and protocols. Although the implementation of Option7-2x is more complex, reduces bandwidth of interface, has advantages in cost and generality.