Post on 18-Mar-2020
Overview of Functional Splits in OAI
Raymond Knopp
Communication Systems Department
EURECOM
Unleashing the potential of open-source in the 5G arena
Considered RAN Splits in 3GPP evolution
Fronthaul/Midhaul
– Lowlatency FH
– Highlatency FH
Central Unit
(CU)
PDCP
LTE-PHY
Radio
LTE-RLC
LTE-MAC
LTE-PHY
5G-RLC
5G-MAC
5G-PHY
5G-PHY
Radio
5G-RLC
5G-MAC
5G-PHY
5G CORE
Low latency FH Split
< 20km
LTE-RLC
LTE-MAC
LTE-PHY
WIFI
MAC
WIFI
PHY
RRC
AMF
High capacity Backhaul Capacity-Limited Backhaul
AMF MEC
Overview of OAI Functional Splits
Distributed
Unit (DU)
UDM AUSF
UPF
UPF
OAI splits (NGFI Numbering)
Overview of OAI Functional Splits
Current OAI implementation (RRU/RAU/RCC)
supports either
• IF5 time-domain fronthaul (> 1 GbE required)
• IF4.5 split (FFTs) (280 Mbit/s/antenna port
fronthaul – 20 MHz carrier) per carrier/sector
• IF1’ = 3GPP F1-U/C under development • IF2 via Cisco open-nfapi
RAN Node Configurations
Overview of OAI Functional Splits
3GPP CU SCF VNF
3GPP
F1-C/F1-U
3GPP DU
CU/DU split in OAI (F1-interface)
Community development
– with 5GPPP 5GPicture project : UThessaly/EURECOM
– Chinese partners (China Mobile, BUPT)
Target OPNFV VCO demonstrator
– with RedHat/Quortus(vEPC)
LTE vs. NR
– F1 is specified for NR and needs to be retrofitted (minor) to
support LTE
– OAI will have F1 support for both
Overview of OAI Functional Splits
Prototype RRU (2.6 GHz/3.5 GHz TDD)
POE
Antenna
10 MHz ref
1GbE
5V
PA/LNA/Switch
Overview of OAI Functional Splits