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HUAWEI TECHNOLOGIES CO., LTD.
Front-haul networking for 5G:
An analysis of technologies and
standardization
Hassan Halabian
Canada Research Center
November 2017
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 2
Cloud-RAN
Advantages:
Simplify the RRH site – Full outdoor, low cost
Better RAN network performance - Facilitates cooperative radio schemes, e.g., ICIC, CoMP, Massive MIMO
Future oriented – RAN virtualization
Fronthaul
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 3
CPRI widely Deployed For 4G
CPRI is - TDM based synchronous
interface/ Symmetrical serial data
link/Steady data stream, ”Always on”
Embedded Ethernet or HDLC streams
(C&M plane data)
I/Q data is the time samples of the wireless
analog signal (Data plane)
Front-haul capacity linearly scales with
Number of antenna ports/Number of sectors
Sampling rate (Radio spectrum BW)/I/Q bit-
width
Transmission overhead (coding and headers,
etc.)/compression factor etc
BER=10-12
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 4
Facing high bandwidth challenge
Big challenge for Massive MIMO (64T/64R) – Beyond
100Gbps requirement
But the real fronthaul bandwidth depends on configuration
– air spectrum bandwidth, Massive MIMO types etc
If Use 4G RAN Architecture for 5G
5
160
0
50
100
4G 5G
(Gbps)
x32with 4:1 compression
20 4
160
64
bandwidth(MHz)
Antenna num
4G
5G
x8 x16
CPRI Split Point
50~130 usBandwidth Boosting Sharply
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 5
eCPRI Protocol Stack
eCPRI Laye1: eCPRI over electrical cable
eCPRI over electrical backplane
eCPRI over optical fiber
eCPRI over Ethernet:
eCPRI messages shall be transmitted in
standard Ethernet frames
eCPRI over IP:
eCPRI messages shall be transmitted in
UDP/IP packets
Ethernet, VLAN (priority tag), MACsec
IP, IPsec
UDP
eCPRI specific protocol layer
User DataReal Time
C&M
eCPRI Services
IP,
IPsec
UDP, TCP,
SCTP, etc.
e.g.
SNMPPTP
C&M Synchronizationother eCPRI
services
SyncE
IP
UDP
Connection OAM
Ethernet
OAM
IP,
IPsec
UDP, TCP
ICMP
Transport Network Layer
Physical Layer
eCPRI Layer
User Sync Control
& Mgmnt
eRadio Equipment Control (eREC)
Transport Network Layer
Physical Layer
eCPRI Layer
User Sync Control
& Mgmnt
eRadio Equipment (eRE)
Transport Network
Fronthaul Network
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 6
When compare CPRI with eCPRI, we found more
challenges
If Use New RAN Architecture for 5G
1: 5G AAU weight increasing
Compared with CPRI part Phy function
embedded in 5G AAU
2: 5G AAU upgrade when add new
features
With Low Phy High Phy
3: Do not forget 4G: CPRI + eCPRI
•Ignore RAN challenges
•eCPRI used for fronthaul
10~25 Gbps
50~130 useCPRI Split Point
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 7
Possible 5G Fronthaul Solutions
Increasing 5G site number faces fiber limitation
Possible transport solutions:
CPRI&eCPRI CPRI&eCPRI
Scenario2: WDM
CPRI&eCPRI
CPRI&eCPRI
Scenario1: Eth based
Scenario3: PON
Limited fiber resource Site number increasing due to 4.5GHz/28GHz
Scenario4: MicrowaveE-band
4G BBU
5G CU/DU
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 8
Eth based Fronthaul Research Introduction
RAN Requirements
Define RRH/BBU Interface Implementation
Fronthaul Requirements Side
•Current focus: Profile(s) for current (CPRI 7.0)
•Next step is eCPRI
• Joint effort with CPRI Cooperation
• Joint effort with IETF DetNet WG
Last PAR 2018/07, SA Revcom approval: 2019/05
802.3br and 802.1Qbu : Frame preemption
802.1Qbv – Traffic Scheduling (time-gated queues)
Ethernet Based Fronthaul Network
• Another Team for Fronthaul based on Eth
• Already demo for CPRI over Eth
• Define new Eth Type for Fronthaul
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 9
IEEE 1914.3 – CPRI over Ethernet
Standard for Radio Over Ethernet (RoE) Encapsulations and Mappings, defines
The encapsulation of digitized radio
mapper/demapper functions to transfer CPRI streams over Ethernet.
The header format for encapsulation of existing digitized radio transport formats.
Three types of encapsulation techniques
structure–agnostic mapper: is only a container for the encapsulated digitized radio transport frames.
structure-aware mapper: has detailed knowledge of the encapsulated digitized radio transport format content
native RoE packet.
1914.3 eCPRI
Technology Only Ethernet UDP/IP/Eth and Eth. - any packet transport
Bandwidth CBR (CPRI encapsulation) and VBR (Native RoE only) User traffic related, VBR( ~10 fold reduction)
Topology P2P connection, P2P/Chain/Ring P2MP connection, flexible topology
RAN IQ time domain and freq. domain data (Native RoE only) Any functional split
Proprietary Performance
Enhancement Support
Limited Yes
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 10
IEEE 802.1 TSN Technology Overview
TSN Standards
LatencyBounded low latency:
Credit Based Shaper (802.1Qav)
Frame preemption (802.3br &
802.1Qbu)
Scheduled Traffic (802.1Qbv)
Cyclic Queuing and Forwarding
(802.1Qch) Asynchronous Traffic
Shaping (P802.1Qcr)
Reliability
Ultra reliability:
Frame Replication and Elimination
(P802.1CB)
Path Control and Reservation (802.1Qca)
Per-Stream Filtering and Policing
(802.1Qci)
Reliability for time sync (P802.1AS-Rev)
SynchronizationTime synchronization:
Timing and Synchronization
(802.1AS) includes a profile of IEEE
1588
Zero congestion loss
Resource Mgmt Dedicated resources & API
Stream Reservation Protocol (802.1Qat)
TSN configuration (P802.1Qcc)
YANG (P802.1Qcp)
Link-local Registration Protocol
(P802.1CS)
Converged network for Information Technology (IT) and Operational
Technology (OT) in LAN
Multi profiles for different applications – Video, Factory, Telecom…
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 11
Eth based Solution – Prototype Test
2016 – Lab POC, CPRI over Eth via PW(same as E1 PW), FlexEth;
No bandwidth saving, device needed when CPRI and eCPRI at the same site
3 × CPRI 7
(9.8304Gbps)encapsulation 40GE(NNI)IF
FPGA based, only lab POC
PW for CPRI
Eth
FlexEth
MAC
Shim PHY
Bonding
MAC
Subrate
EthChannelized
CPRI
Encapsulation of CPRI frame Multiplexing with FlexE
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 12
WDM Based Solution – FO/Colorless Module
15*Any Port
GE~10G
• Full Outdoor, w/o
site configuration
• Bi-Di, with 1+1
protection
• w/o optical layer
commissioning
O/E
Map/
Demap
OTN
OH oDSP
Colorful IF
E/O
2x50G
Current FO Solution
BBUOSN 1800
Centralized WDM Solution(Under R&D)
AAU
AAUCloud BB
Colorless SFP+
BiDi
Optical distribution
box
Shared laser (10 directions)passive
multiple wavelengths
Shared laserColorless SFP+(10G/25G)
…
GC Site
Compatible with CPRI/eCPRI – transparent for any traffic
Simple, low power consumption and save site fibers – without device
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 13
PON Based Solution–– Optimized DBA Algorithm
DBA logic
DBA report
Allocation
Time slot
SR T-CONT
NSR T-CONTScheduler
ONUPON Board - OLT
Control plane
Date plane
Current NG-PON DBA :350~550us DBA Optimization for 5G:50us~100us
• Assured-DBA/Max DBA, status report before bandwidth allocation : 1-2ms.
• Fixed-DBA, no need status report, delay will be 100-200us
• Periodic windowing, add delay 200-300us
SR-DBA
NSR-
DBA
Periodic
windowing
DBA logic
SR-DBA
NSR-
DBA
Periodic
windowing
DBA logic
SR-DBA
NSR-
DBA
New Periodic
windowing
Mechanism
LL-DBA
• LL-DBA, low latency DBA in future, delay will be about 50us~100us.
• Periodic windowing should have new mechanism to eliminate latency to
0.Notes: chipset and hardware must be changed to
support 50us~100us low latency DBA
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 14
Fronthaul Solution Summary
1WDM - Colorless
2Eth – RoE
4PON
• Transparent for CPRI/eCPRI: 4G&5G Compatible
• No site device: Simple, low power consumption
• Innovation: new optical module
• CPRI mapper/demapperneeded
• Limited functional splitting available
• Utilize the L2 switch supply chain
• Only Eth transport
• Reuse the existing ODN
• Upgrade PON capacity and optimize the DBA algorithm
3IP/Eth – eCPRI
• Open for performance enhancement
• Support any packet transport
• Flexible function splitting
• No support for CPRI
Thank youwww.huawei.com
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