Method and apparatus for flexible fronthaul physical layer split for cloud radio access networks

摘要

A cloud radio access network (CRAN) system includes a baseband unit (BBU) and a radio unit (RU) remote from the BBU. The fronthaul interface between the RU and the BBU includes a radio frequency interface (RF) functionality implemented in the RU, and implementation of asymmetrical physical layer (PHY) functionality split between the BBU and RU. The asymmetrical physical layer (PHY) functionality split includes: downlink (DL) antenna port mapping and DL precoding implemented in the RU; and the split of the PHY functionality for uplink (UL) at the antenna port mapping in the BBU. For the DL, precoding and resource element (RE) mapping to frequency resources is implemented in BBU, and RE mapping for antenna ports is implemented in the RU|[WA1]. The split also provides support for license-assisted access (LAA) in the CRAN system.