ran functional decomposition the options and interfaces… · nodeb iub interface rnc nokia umts...
TRANSCRIPT
British Telecommunications plc 2018
RAN Functional Decomposition the options and interfaces…
Andy SuttonPrincipal Network ArchitectArchitecture & StrategyBT Technology 19th November 2018
British Telecommunications plc 2018
Contents
• RAN architecture evolution
• RAN functional decomposition
• Access network connectivity
• 5G network deployment
• 5G demo update
• Summary
2
British Telecommunications plc 2018
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
• Distributed intelligence with centralised BSC
3
BTS Abis interface BSC
Nokia GSM Ultrasite BTS
Core network
NOTE: IP Sec GW used between BTS and BSC with IP Abis implementation
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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
• Distributed radio with centralised intelligence
4
NodeB Iub interface RNC
Nokia UMTS Ultrasite BTS
Core network
British Telecommunications plc 2018
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
5
eNB S1 interface EPC
Huawei 3900 eNB (+GSM BTS)
eNB S1 interface SecGW Core network
2600MHz RRU
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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 CPRI interface
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RRU CPRI BBU
Huawei 3900 eNB (+GSM BTS)
RRU CPRI BBU S1 interface
2600MHz RRU
S1 interface
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Base station architecture - LTE
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RRU BBU
RRU
S1 interface
BBU S1 interface
RRU BBU S1 interface
CPRI
CPRI
D-RAN with cabinet RFU
D-RAN with external RRU
C-RAN with centralised BBU
Note: a site may support
one or more base station
architectures for different
radio channels/bands
British Telecommunications plc 2018
RAN functional splits - protocol architecture
8
RRC
PDCP
Data
Low-RLC
High-MAC
High-PHY
Low-MAC
Low-PHY RF
High-RLC
RRC
PDCP
Data
Low-RLC
High-MAC
High-PHY
Low-MAC
Low-PHY RF
High-RLC
Option1
Option2
Option3
Option4
Option5
Option6
Option7
Option8
Relaxed Very lowEnd to end latency
Traffic/capacity related Very highCapacity requirement
Higher layer splits Lower layer splits
S1
CPRI
Reference 3GPP TR 38.801
British Telecommunications plc 2018
RAN functional decomposition
9
gNB
RU* DU CU
* RU could be integrated within AAU (mMIMO) or standalone RU (RRU/RRH) with coaxial connections to passive antenna (typically 8T8R)
CPRI
eCPRI
F1
interface
S1 interface (EPC+)
N2/N3 interfaces (NGC)
NR (air)interface
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RAN functional decomposition - E1 interface
10
gNB
RU* DU
CU-c
* RU could be integrated within AAU (mMIMO) or standalone RU (RRU/RRH) with coaxial connections to passive antenna (typically 8T8R)
CPRI
eCPRI
F1-cNR (air)
interface
CU-uF1-u
N2
N3
E1
Additional work is on-going on:
• DU-CU split for LTE (W1
interface)
• E2 interface between CU and
RAN Intelligent Controller (RIC)
• A1/O1 interface between RIC
and NMS & Orchestration layer
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Base station architecture - 5G - EN-DC (Option 3x)
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RU CU
RU
S1 interface
DU
RU DU
D-RAN with AAU/RRU
C-RAN with option 2 split
C-RAN with option 7/8 split
and further CU centralisation
DUCPRI
eCPRI
CU S1 interfaceF1CPRI
eCPRI
CU S1 interfaceF1CPRI
eCPRI
Note: a site may support
one or more base station
architectures for different
radio channels/bands
Note: In full C-RAN configuration the DU and CU may be co-located or on separate sites
British Telecommunications plc 2018
RAN functional splits - protocol architecture
12
RRC
SDAP/PDCP
Data
Low-RLC
High-MAC
High-PHY
Low-MAC
Low-PHY RF
High-RLC
RRC
SDAP/PDCP
Data
Low-RLC
High-MAC
High-PHY
Low-MAC
Low-PHY RF
High-RLC
Option1
Option2
Option3
Option4
Option5
Option6
Option7
Option8
Relaxed Very lowEnd to end latency
Traffic/capacity related Very highCapacity requirement
Higher layer splits Lower layer splits
S1
CPRIeCPRIF1
Reference 3GPP TR 38.801
Note:Service Data Adaptation Protocol (SDAP), has been introduced to the NR userplane to handle flow-based Quality of Service (QoS) framework in RAN, such asmapping between QoS flow and a data radio bearer, and QoS flow ID marking.
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Base station architecture - 5G - Next Generation Core (NGC)
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RU CU
RU
N2/N3 interface
DU
RU DU
D-RAN with AAU/RRU
C-RAN with option 2 split
C-RAN with option 7/8 split
and further CU centralisation
DUCPRI
eCPRI
CU N2/N3 interfaceF1CPRI
eCPRI
CU N2/N3 interfaceF1CPRI
eCPRI
Note: a site may support
one or more base station
architectures for different
radio channels/bands
Note: In full C-RAN configuration the DU and CU may be co-located or on separate sites (as illustrated)
British Telecommunications plc 2018
RAN functional splits - protocol architecture
14
RRC
SDAP/PDCP
Data
Low-RLC
High-MAC
High-PHY
Low-MAC
Low-PHY RF
High-RLC
RRC
SDAP/PDCP
Data
Low-RLC
High-MAC
High-PHY
Low-MAC
Low-PHY RF
High-RLC
Option1
Option2
Option3
Option4
Option5
Option6
Option7
Option8
Relaxed Very lowEnd to end latency
Traffic/capacity related Very highCapacity requirement
Higher layer splits Lower layer splits
N2-N3
CPRIeCPRIF1
British Telecommunications plc 2018
RAN access network connectivity
15
RU DU CUS1 or N2/
N3 interface
F1CPRI
eCPRI
Terms; Fronthaul, mid-haul and backhaul as defined by MEF (Metro Ethernet Forum)
Fronthaul Mid-haul Backhaul
Backhaul (in common use)
CPRI, eCPRI orNon-ideal fronthaul
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5G within a multi-RAT network deployment - DRAN scenario
16
3G
4G1
5G
CSGOSA-FC
OSA-FC
21CMSE
DWDM
DWDM
21CMSE
Mobile core
networks2
21C IP/MPLS network (P routers not illustrated)
Openreach Point to point DWDM solution
Future-proofed for network sharing and RAN evolution
n x λ(can bypass
CSG)
1 - 2G 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
PRTC sync source
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5G within a multi-RAT network deployment - DRAN scenario
17
3G
4G1
5G
CSGOSA-FC
OSA-FC
21CMSE
DWDM
DWDM
21CMSE
Mobile core
networks2
21C IP/MPLS network (P routers not illustrated)
Openreach Point to point DWDM solution
n x λ(can bypass
CSG)
1 - 2G 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
PRTC sync source
E-Band
British Telecommunications plc 2018
5G within a multi-RAT network deployment - DRAN scenario
18
3G
4G1
5G
CSGOSA-FC
OSA-FC
21CMSE
DWDM
DWDM
21CMSE
Mobile core
networks2
21C IP/MPLS network (P routers not illustrated)
Openreach Point to point DWDM solution
n x λ(can bypass
CSG)
1 - 2G 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
PRTC sync source
E-Band
E-band link(s) could connect directly to a wavelength on OSA-FC product
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5G demo at Canary Wharf
19
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 2100 + 15 MHz 2600) with 64T64R NR
British Telecommunications plc 2018
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 (CPRI based) is popular in Asia due to availability of dark
fibre, this brings radio optimisation benefits through centralised scheduling etc.
• CPRI doesn’t scale for 5G due to amount of spectrum and antennas therefore eCPRI
was developed by the same industry partners who developed CPRI
• 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
https://www.ngmn.org/fileadmin/ngmn/content/downloads/Technical/2018/180226_NGMN_RANFSX_D1_V20_Final.pdf