IMPACT OF 5G RAN ARCHITECTURE IN TRANSPORT NETWORKS Daniel Camps (i2cat) ONDM 2018 Optical Technologies in the 5G era (Workshop) Bristol 5G city testbed with 5G-XHaul extensions
OUTLINE From 4G to 5G architecture The F1 interface and new RRC states The F2 interface (3GPP and ) 5G deployment options 5GXHAUL/5GPICTURE s view on a converged 5G transport Thoughts on transport support for 5G QoS Conclusions 2
FROM 4G TO 5G ARCHITECTURE 3 E-UTRAN (LTE) enb (RRH-BBU) UE X2 S1-MME S1-U Serving Gateway PDN Gateway S5 S10 HSS S6a PCRF Gx PDNs APNs SGi U-Plane C-Plane EPC MME S11 S1-C 5GNR gnb-cu UE Xn N2 N3 UPF UPF N9 N14 AUSF PCF DNNs APNs N6 U-Plane C-Plane 5GCore gnb-du F1 RRH F2 SMF N4 AMF N1 1 NSSF N7 N1 (S-NSSAI) N1 2 N22
F1 INTERFACE AND NEW RRC STATES gnb-cu IP flow anchoring Non-Real time SDAP PDCP RRC gnb-du F1 RLC MAC PHY Real time F1 RLC MAC PHY Real time Xw WT 802.11 Non-3GPP Control Plane User Plane Radio Network Layer Transport Network Layer F1AP SCTP IP Data link layer Physical layer Radio Network Layer Transport Network Layer GTP-U UDP IP Data link layer Physical layer F1 functions: Mgmt CU-DU (discovery, reset, etc) SIB delivery from CU to DU UE context mgmt: F1 sessions maintained per UE 4
F1 INTERFACE AND NEW RRC STATES AMF UE RRC STATES N2 N2 Xn gnb-cu gnb-cu F1 F1 F1 RRC Connected N3: ESTABLISHED F1: ESTABLISHED RRC Idle N3: RELEASED F1: RELEASED gnb-du gnb-du gnb-du intra-cu F1 handover inter-cu F1 handover RRC Innactive N3: ESTABLISHED F1: RELEASED Location kept by gnb-cu in terms of RNA (RAN Notification Areas) UE 5
F2 INTERFACE (3GPP AND ECPRI) Not much progress inside 3GPP à Work in parallel carried out by A variety of potential splits considered Split A split B split C split D split I D split II D split I U I/Q Freq. Domain split E I/Q Time Domain 5GPICTURE D4.1 - http://www.5g-picture-project.eu/ 6
F2 REQUIREMENTS SUMMARY From spec 3/1.5 Gbpsuserthroughput 500 PRBs 8/4 DL/UL MIMO layers 64 Antennas Digital BF in erec 256QAM IQ 30 bits/sample 7
F2 INTERFACE SCALABILITY [1] Split E Split IID Split B Split E Split IID Split B 4G 4G 400G Ethernet (IEEE P802.3bs) àsupports all splits/rats àfor 5G split E /full centralization only a few cells can be aggregated in one link 10G Ethernet, ~CPRI rate 8 àcan support only 4G, low load/split C, no support of 5G split E /full centralization [1] Bartelt, Jens, et al. "5G transport network requirements for the next generation fronthaul interface." EURASIP Journal on Wireless Communications and Networking 2017.1 (2017): 89. 8
5G DEPLOYMENT OPTIONS mmwave 60GHz C DU U D U mmwave 26/28GHz (reqs. > 10 GBps) D U C DU U D U D U 100 MHz 3.5 GHz (reqs.~ 10Gbps (F1)) RR H MEC Access fibre, e.g. WDM-PON App server Small Cell - CU Access Macro- DU Macro- CU UPF MEC App server Aggregation UPF MEC App server Core UPF 5GCore Internet App server NFVI NFVI NFVI UPF location [1] Access Aggregation Core Num. Sites 1200 106 10 Transport latency Estimated 5G latency (*) 0.6 ms 1.2 ms 4.2 ms 9.2/2.2 ms (embb/urllc) 10.4/3.4 ms (embb/urll C) 16.4/9.4 ms (embb/urllc) (*) 5G-RAN target OWD delays: 4 ms embb, 0.5 ms URLLC [1] Andy Sutton, BT, 5G Network Architecture, available at: https://www.youtube.com/watch?v=ageaqj7u1ta 9
5GXHAUL/5GPICTURE S VIEW ON A MULTI-TENANT 5G TRANSPORT Data Plane Data plane - ETN (interface PNF/VNF) IATNs (stich transport domains) - Per-tenant state at the edge - MACinMAC transport (pathid+sliceid) Control Plane Control plane - Hierarchical - L0 tech domain aware - L1 tech domain agnostic - RAN Transport interface - Synch Harmonizer 10
THOUGHTS ON TRANSPORT SUPPORT TO 5G QOS F1, N3, Xn, Xw interfaces are all based on GTP GTP TEID identifies per-ue sessions GTP extension header will carry the 5G QoS Flow ID (QFI) Can we directly map 5G QoS to transport flows (at least at the edge)? i.e. establish transport flows according to UE s RRC transitions Analysis performed based on an operational LTE network in Greece (33 cells) State maintained at each transport node Signalling load with transport controller 11
SUMMARY AND CONCLUSIONS 5G RAN base station decomposed into RRH DU CU Backhaul-like F1 interface below PDCP between CU and DU Multiplicity of options (functional splits) between DU and RRH 5G s flexibility provides built-in support for low latency applicationswithin the network 12
Thanks for your attention! Questions?