RAN Functional Decomposition the options and interfaces

Transcription

1 RAN Functional ecomposition the options and interfaces Andy Sutton Principal Network Architect Architecture & Strategy BT Technology 19 th November 2018

2 Contents RAN architecture evolution RAN functional decomposition Access network connectivity 5G network deployment 5G demo update Summary 2

3 GSM - fully distributed RAN GSM BTS is a fully distributed radio base station All radio related protocols terminate in the BTS Radio interface encryption terminates in the BTS istributed intelligence with centralised BSC BTS Abis interface BSC Core network NOTE: IP Sec GW used between BTS and BSC with IP Abis implementation Nokia GSM Ultrasite BTS 3

4 UMTS - many centralised functions UMTS is a simple L2 radio base station (known as Node B) All radio related protocols terminate in the RNC Radio interface encryption terminates in the RNC istributed radio with centralised intelligence NodeB Iub interface RNC Core network Nokia UMTS Ultrasite BTS 4

5 LTE - distribution wins again LTE enb is a fully distributed radio base station All radio related protocols terminate in the enb Radio interface encryption terminates in the enb X2 interface between adjacent enbs, no centralised network controller 2600 MHz RRU enb S1 interface EPC enb S1 interface SecGW Core network Huawei 3900 enb (+GSM BTS) 5

6 LTE - RAN options LTE enb is a fully distributed radio base station However, this radio (enb) is made up of two components which can be geographically separated RRU/RRH and BBU - separated by interface 2600 MHz RRU RRU BBU S1 interface RRU BBU S1 interface Huawei 3900 enb (+GSM BTS) 6

7 Base station architecture - LTE -RAN with cabinet RFU RRU BBU S1 interface Note: a site may support one or more base station architectures for different radio channels/bands -RAN with external RRU RRU BBU S1 interface C-RAN with centralised BBU RRU BBU S1 interface 7

8 RAN functional splits - protocol architecture RRC Higher layer splits Lower layer splits PCP RF ata S RRC PCP RF ata End to end latency Relaxed Very low Capacity requirement Traffic/capacity related Very high 8 Reference 3GPP TR

9 RAN functional decomposition gnb NR (air) interface F1 RU* U CU e interface S1 interface (EPC+) N2/N3 interfaces (NGC) 9 * RU could be integrated within AAU (mmimo) or standalone RU (RRU/RRH) with coaxial connections to passive antenna (typically 8T8R)

10 RAN functional decomposition - E1 interface gnb Additional work is on-going on: U-CU split for LTE (W1 interface) E2 interface between CU and RAN Intelligent Controller (RIC) A1/O1 interface between RIC and NMS & Orchestration layer NR (air) interface RU* e U F1-c F1-u CU-c E1 CU-u N2 N3 10 * RU could be integrated within AAU (mmimo) or standalone RU (RRU/RRH) with coaxial connections to passive antenna (typically 8T8R)

11 Base station architecture - 5G - EN-C ( 3x) -RAN with AAU/RRU RU e U CU S1 interface Note: a site may support one or more base station architectures for different radio channels/bands C-RAN with option 2 split RU e U F1 CU S1 interface C-RAN with option 7/8 split and further CU centralisation RU e U F1 CU S1 interface 11 Note: In full C-RAN configuration the U and CU may be co-located or on separate sites

12 RAN functional splits - protocol architecture RRC Higher layer splits Lower layer splits SAP/ PCP RF ata S RRC SAP/ PCP RF End to end latency Capacity requirement ata Relaxed Traffic/capacity related F1 e Very low Very high Note: Service ata Adaptation Protocol (SAP), has been introduced to the NR user plane to handle flow-based Quality of Service (QoS) framework in RAN, such as mapping between QoS flow and a data radio bearer, and QoS flow I marking. 12 Reference 3GPP TR

13 Base station architecture - 5G - Next Generation Core (NGC) -RAN with AAU/RRU RU e U CU N2/N3 interface Note: a site may support one or more base station architectures for different radio channels/bands C-RAN with option 2 split RU e U F1 CU N2/N3 interface C-RAN with option 7/8 split and further CU centralisation RU e U F1 CU N2/N3 interface 13 Note: In full C-RAN configuration the U and CU may be co-located or on separate sites (as illustrated)

14 RAN functional splits - protocol architecture RRC Higher layer splits Lower layer splits SAP/ PCP RF N 2 - N 3 ata RRC SAP/ PCP RF ata F1 e End to end latency Relaxed Very low Capacity requirement Traffic/capacity related Very high 14

15 RAN access network connectivity F1 RU U CU e S1 or N2/ N3 interface, e or Non-ideal fronthaul Fronthaul Mid-haul Backhaul Backhaul (in common use) 15 Terms; Fronthaul, mid-haul and backhaul as defined by MEF (Metro Ethernet Forum)

16 5G within a multi-rat network deployment - RAN scenario Openreach Point to point WM solution PRTC sync source 21C IP/MPLS network (P routers not illustrated) 3G 4G 1 5G CSG OSA -FC n x λ (can bypass CSG) OSA -FC 21C MSE W M W M 21C MSE Mobile core networks 2 Future-proofed for network sharing and RAN evolution G is supported on the same base station as 4G (SRAN/Multi-RAT) 2 - Includes RNC for 3G and IP Sec GW for 4G and 5G

17 5G within a multi-rat network deployment - RAN scenario Openreach Point to point WM solution PRTC sync source 21C IP/MPLS network (P routers not illustrated) 3G 4G 1 5G CSG OSA -FC n x λ (can bypass CSG) OSA -FC 21C MSE W M W M 21C MSE Mobile core networks 2 E-Band G is supported on the same base station as 4G (SRAN/Multi-RAT) 2 - Includes RNC for 3G and IP Sec GW for 4G and 5G

18 5G within a multi-rat network deployment - RAN scenario Openreach Point to point WM solution PRTC sync source 21C IP/MPLS network (P routers not illustrated) 3G 4G 1 5G CSG OSA -FC n x λ (can bypass CSG) OSA -FC 21C MSE W M W M 21C MSE Mobile core networks 2 E-Band E-band link(s) could connect directly to a wavelength on OSA-FC product G is supported on the same base station as 4G (SRAN/Multi-RAT) 2 - Includes RNC for 3G and IP Sec GW for 4G and 5G

19 5G demo at Canary Wharf Highlights 1.3Gbps to test equipment (30 MHz LTE + 40 MHz NR) 600Mbps to Huawei 5G CPE (5 MHz LTE + 40 MHz NR) 4T4R LTE (15 MHz MHz 2600) with 64T64R NR 19

20 Summary The functional decomposition of the RAN is at an advanced stage in standards, industry fora and implementation (XRAN/ORAN, 3GPP, ONAP) Traditional 4G centric CRAN ( based) is popular in Asia due to availability of dark fibre, this brings radio optimisation benefits through centralised scheduling etc. doesn t scale for 5G due to amount of spectrum and antennas therefore e was developed by the same industry partners who developed Several industry groups are working towards a virtualised RAN to disaggregate the hardware from software for many functions, also enables innovative new entrants to market Major RAN vendors offer a range of different RAN architectures to meet various deployment scenarios BT is currently rolling out the radio, backhaul and core network infrastructure necessary to be a leader in 5G and converged networks 20

21 Thank You Any questions? 21