Description of OAI-based C-RAN Testbed
Cloud or Centralized radio access network (C-RAN) is an innovative cellular network architecture where the traditional base station functionality is split into baseband processing units (BBUs), which are pooled in a cloud data center, and remote radio heads (RRHs), that are present at cell sites. C-RAN has drawn significant attention as the emerging architecture of future generation cellular networks, due to its noticeable performance benefits for cellular operators. In C-RAN, each RRH will forward the user information to the central cloud processor (BBU pool) using high bandwidth, low latency fronthaul link, and thereby relies on the BBU pool to perform the compute intensive baseband functions.
C-RAN testbed architecture consists of RRU/RRH, BBU/RCC, EPC, and HSS was built, installed and configured using OpenAirInterface (OAI) platform and software defined radio (SDR) frontends. The CRAN testbed architecture was implemented through two LTE UEs by using two USRPs (B210) connected to the desktop machine through USB 3.0. One RRU/RRH is implemented using USRP X310 (2TX/2RX) connected to the desktop machine through PCIe interface with rate 200MS/Sec. The BBU/RCC, EPC, and HSS are implemented using OAI on intel-based desktop machines. Synchronization clock module is used to provide the required reference clock for all USRPs for whole system synchronization. The RRH is connected to the BBU/RCC through Ethernet fronthaul link. The network connectivity for the implemented C-RAN architecture is tested using the COST mobile terminal as well as OAI user equipment (UE) in which different performance metrics are generated.