Post on 02-Oct-2021
Anritsu Handheld ProductsFor Testing CPRI
November 2016
José María Pindado Buendía
Engineering & Technology, EMEA
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Agenda
• Introduction• C-RAN Technology Overview• Tests required and solutions for CPRI Network
– Optical Test– CPRI Test– RFoCPRI Test
• Summary
MT1000A/MT1100A Training FY 2015
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Mobile operator challenges migration to C-RAN
• Operators are having to support an explosive spread of smartphones and tablets thus increasing demand for bandwidth, several challenges present to them:• Increasing Quality, bandwidth and coverage of the
communication• cost optimisation. The Euro per bit continues to decrease• To be prepare network next generation, the 5G• Reduce Energy consumption
• Adoption of Centralized-Radio Access Networks (C-RAN) is key for operators to achieve mobile network migration.
• New protocols are used over C-RAN• Common Public Radio Interface (CPRI) • Open Base Station Architecture Initiative (OBSAI)
Traffic (EB / Month) 2014 2019 GrowthFixed/Wired 32.4 55.7 11%Fixed/Wi-Fi 24.9 88.1 29%Mobile/Cellular 2.5 24.3 57%
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Agenda
• Introduction• C-RAN Technology Overview• Tests required and solutions for CPRI Network
– Optical Test– CPRI Test– RFoCPRI Test
• Summary
MT1000A/MT1100A Training FY 2015
5
Tower Evolution N
ode B
PS
AC
.
Switch
RRH
BB
U
PS
A\C
Switch
RRH
PS
A\CSwitch
RRH
PS
A\CSwitch
RRH
PS
A\CSwitch
RRH
4 P
ort
B
BU
Switch
PS
A\C
Heavy high loss Coax
Dedicated equipment high
Power consumption
Remote Radio
Head Unit
Optical Fiber and
Power feed
Less equipment lower Power consumption
Minimum equipment lowest
Power consumption
Single BBU serving multiple
RRH Units.
The migration to C-RAN
Yesterdays network
Todays networkRRH
Deployment
Tomorrows networkC-RAN
OTN / MPLS-TP
Metro Network
Current Transport Network
1 Gbps or 10 Gbps
Ethernet link
Ethernet / SDH/SONET
/ OTNNetwork
PS : Power SupplyAC : Air Conditioner
BBU : Base Band UnitRRH : Radio Remote HeadC-RAN : Centralized-Radio Access Networks
BTS
RRHRRH
RRHRRH
RRHRRHRRHRRH RRHRRH
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What is CPRI
CPRI is digital interface standards for transmitting digitized RF signals from RRH to BBU.It defines framing, coding, control, synchronisation …managing the up and down traffic.
• It’s standard developed in cooperation with several manufacturers Ericsson, Huawei, NEC, ALU and Nokia.
Today CPRI interfaces are being deployed for RRH configuration.Tomorrow CPRI will be extended in the Mobile FrontHaul, some trials are done with the operators
.
CPRI
7
Mobile networks, CPRI where they fit IN
• This move to the C-RAN creates a new domain within the mobile network. • The new network between the BBU and the RRH in the cell site is referred to as the
fronthaul network• The network between the BBU and the core network is still the mobile backhaul
network – Physical layer, normally optical (electrical is standardized)
Mobile FronthaulMobile Backhaul
RRH: Remote Radio HeadBBU: Base Band UnitCO : Central Office
CPRI
CoreNetwork
Optical Link
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BBU 4GBBU 4G
CWDM(up to 18 CPRI)
Passive opticalmux and Dmux
Active transponder
CPRI onDWDMNetwork
Active Front-HaulPassive Front-Haul
Distance between BBU and RRH relies on latency specification. The max distance is 40km.
Front Haul configuration
Distribution box
RRH
RRHRRH
RRH
RRHRRH
Ant up 1
RRH
RRHRRH
BBUBBU
BBU 3GBBU 3GAnt up 1
RRH
RRHRRH
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CPRI System Architecture
(The CPRI standard uses other names, RU (Radio Unit)= RRH & DU (Digital Unit) =BBU
C&M : Control and Management
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CPRI (option 1) basic frame structure (128 bits)
The basic frame is Tc = 1/fc, Tc = 1/3.84 MHz, = 260.417n
CPRI System architecture
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• The Hyperframe– 256 basic frames
• 256 control words (the green section is the control words) organized in 64 sub channels, 4 words each.
– 66.67 µs (256*260.417) long• The CPRI (or eNodeB) Frame
– 150 hyperframes– 10 ms (66.67*150) long
• BFN (NodeB Frame Number)
The CPRI 10 ms Frame
#0 #Z #149CPRI 10ms Frame
#0 #X #255
1...8
B0
B = T-1
W
Y
Hyperframe
BFNMany NodeB Frames
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CPRI rate and capability
• CPRI link capacity per option
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CPRI capacity vs Radio format
Required CPRI link capacity depending on radio technologies
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• Rates 1 through 7 use 8B/10B line coding
• New rates (7A, 8 & 9) use 64B/66B line coding
• Option/Line Rate 7A will be used for Machine to Machine(internal)• Don’t need to worry about for our
testing• Option/Line rate 8 = 10137.6 Mbit/s• Option/Line rate 9 = 12165.12 Mbit/s• Option/Line rate 10 = 24330.24 Mbit/s
CPRI Bit Rates increase
Option / Line Rate
Bit Rate (Gbps) Line Code
1 0.6144 8B/10B2 1.2288 8B/10B3 2.4576 8B/10B
4 3.0720 8B/10B5 4.9152 8B/10B6 6.1440 8B/10B7 9.8304 8B/10B
7a 8.1101 64B/66B8 10.1376 64B/66B9 12.1651 64B/66B
10 24.3302 64B/66B
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Agenda
• Introduction• C-RAN Technology Overview• Tests required and solutions for CPRI Network
– Optical Test– CPRI Test– RFoCPRI Test
• Summary
MT1000A/MT1100A Training FY 2015
16
C-RAN network is optical :
Many fibers Multi Mode and Single Mode- Fibers from RRH to cabinet, some tens of
meter - Cabinet to BBU some hundreds of meter
(<40km)
Many connectors Mainly LC type
Many transceivers SFP- Several types:
- Black and white- Colored- Single or two fibers
Mux and Demux (active or passive)
C-RAN network and Optical devices
RRH
RRHRRH
Distribution at bottonof the antenna
RRH
RRHRRH
Ant up 1
BBUBBU
Distribution insideBBU building
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Depending on the operators, the procedure to test the optical network can be slightly different.
Installation and maintenance : tests are required• Connector cleaning• Fiber Characterization• Optical power and budget• Fiber identification
Tools are also required :• Microscope (a Visual inspection Probe)• Optical Time Domain Reflectometer (OTDR)• Power Meter & Optical Loss Test set (OLTS)• Visual Light source (VLS)
Optical tests for installation & Maintenance
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RRH
BBU
RRH
CabinetDistribution
LC connectors
LC to LCconnectors
Tens ofmeters
<40km
Using an OTDR It tests the optical link (fiber + connectors)
Capable to measure fibers and to find some events on optical link : loss, reflection, bending, splice & connector
With the MT1000A OTDR :• FiberVisualizer mode : OTDR tests easy to understand with a
Pass/Fail evaluation
• OTDR mode : Usual visualization with trace and event table
• Multimode 850 and 1300nm and Singlemode 1310 and 1550nm
• Distance test range >> 40km
• Dead Zone : Event 0.8m , Attenuation 3.8m
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Using Visual Inspection Probe VIP
G0306A Video Inspection Probe
Cleanup
Cleanup
A simple dust onto a connector can stop the optical link.
VIP tests ensure the connectors are clean.
Anritsu VIP can be connected on the MT1000A or a PC • Function for detecting presence of scratches and dirt on optical connector• Displays results as Pass/Fail evaluation based on IEC61300-3-35 standard• Supports various connector types
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Using OLTS (Optical Loss Test Set)
With the MT1000A or CMA5
• Source: Multimode 850 and 1300nm and Singlemode 1310 and 1550nm
• ~50dB dynamic
• With MT1000A
• Measurement results managed with Loss Table
• Pass/Fail evaluation using preset threshold values
RRH
RRH
Tens ofmeters
It tests the optical link (fiber + connectors) For short distance & Quick tests
NOT able to find events on the distance
Loop is required if tests are done at the bottom of the antenna
CMA5source
CMA5PowerMeter
CMA5OLTS
MT1000A OLTS
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VFL OPM
Using Visual Fault Locator (VFL)& Optical Power Meter (OPM)
Many Fibers and connectors to be linked at the right place. • Visually the VFL ensures the right connection• The OPM ensures the power level is enough
With the MT1000A• VFL, Emitting Red light. Modulate On/Off• Optical Power Meter -67 to +6dBm @ 800 to 1700nm
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Anritsu solution : MT1000A
9” high-resolution
touch panel
Power switch
Tests covered:
- OTDR MM and SM
- Visible source
- Power meter
- Visual Inspection Probe
- OLTS
Visible Light Source Option
Back panel Cover
OTDR ModuleMU100020A/21A
Main FrameMT1000A
Optical Power Meter
OTDR Multimode Port (850/1300 nm)
OTDR Single-Mode Port (1310/1550 nm)
Audio AUX(Interface for GPS)
Clock Input
USBMini-B
USB A
USB A
Ethernet Interface (for Remote Control)
DC Input (18 Vdc)
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Agenda
• Introduction• C-RAN Technology Overview• Tests required and solutions for CPRI Network
– Optical Test– CPRI Test– RFoCPRI Test
• Summary
MT1000A/MT1100A Training FY 2015
24
C-RAN network and CPRI protocol
C-RAN network uses frames between BBU and RRH.
• Transmission section– Physical layer, normally optical (electrical is standardized)
• Bit rate and 8B/10B line coding or 64B/66B line coding– Standard requires transmission error
free at a rate of BER < 10-12
• Time Division Multiplexing section– Aligns each higher layer to
“time on the wire”
• Layer 2:– Control word:
• L1 In-band protocol• C&M data• Vendor Specific data
– IQ Data (RF data)
Laye
r 2La
yer 1
IQ D
ata
User Plane
Vend
or S
peci
fic
Eth
erne
t
Control & Management Plane SYNC
Electrical Transmission
Optical Transmission
Time Division Multiplexing
HD
LC
L1 In
-ban
d Pr
otoc
ol
C&M : Control & Management
Frame
RRH
RRHRRH
RRH
RRHRRH
Ant up 1
BBUBBU
Frame
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L1-InBand CPRI protocol
Extract from Figure 30 in CPRI Specification V6.1: Start-up states
and transitions
Standby
L1 synchronization
Protocol setup
C/M plane (L2+) setup
Interface and vendor specific
negotiation
Operation
Passive link
No C&M
C&M proposed
A
B
C
D
E
F
G
State
C&M Control & Management
RF signal is carried into the payload of the frame.
Before carrying RF signal, the L1-InBand protocol establishes the connection between equipment.
Standby to Operation sequence allows to connect the equipment.
Alarms and Errors are reported in case the sequence failed:• LOS : Loss of Signal • LOF :Loss of Frame • Reset : Master send Reset to Slave• RDI : Remote Default Indication• SDI : SAP Default Indication
Frame
RRH
RRHRRH
RRH
RRHRRH
Ant up 1
BBUBBU
Frame
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Transport CPRI - What’s tested and why• Testing up to the “Passive Link” (or to the “G” state)
– Allows to confirm that that BBU and RRH communication is OK• Optical power, wavelength (correct SFP), frequency, etc...• Confirms L1In-band sequence and show Alarm/error
• BERT (May require loopback)– Ensures network meets the required <10-12 requirement
The payload is filling in PRBS sequence (instead of RF)
• Delay (Requires loopback)– Ensures the minimum delayspecification in C-RAN is met
• Automatic Protection switching– For protected network, ensures theAPS sequences works correctly
①②
Tester
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CPRI - Test cases for Installation and Maintenance
• Test case 1– Connect to actual Equipment
• SFP & frequency tests• Monitor Errors/alarms/link• Check equipment behaviour
• Test case 2– Terminate both sides of the transmission line
(one side could be in loopback)• BER test• Delay measurement• APS (Automatic Protection switching)
• Test case 3– Monitoring of the actual line between
BBU and RRH• Utilizing through mode to monitor interactive
behaviour of equipment
Test case 2
Test case 3
Test case 1
Splitter
Splitter
Monitoring situationOnly for Maintenance
Emulation test situation
System test situation
Tester
Tester
Tester Tester
RRH
BBU
RRH BBU
Tester
Tester
C-RAN
Tester LoopC-RAN
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MT1000A Tester for TransportCPRI Product Features
CPRI/OBSAI L1 Test• Supported bit rates
– CPRI: 614.4, 1228.8, 2457.6, 3072.0, 4915.2, 6144.0, 9830.4, 10137.6 Mbps
– OBSAI: 768, 1536, 3072.0, 6144.0 Mbps• Clocks: Internal, External (10 MHz), GPS• Level (dBm), Bit rate and deviation (ppm) tests• Alarm/Error detection (Signal Loss, PSL, Pattern Error)• Unframed BER measurement• Automatic Protection Switching (APS) tests
MT1000A
BBU
BBU
SFP
BBU
RRU
SFP
Two ports, - Independent Generator/analyzer- Pass-through monitoring
Select the bit rate
Status & frequency tests
Alarm, error,statistics
APS tests, Switching time depending on events
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MT1000A Tester for TransportCPR Product Features
• CPRI L2 Test– Link status monitoring– Alarm/Error detection (Signal Loss, LOS, LOF, R-LOS, R-LOF, RAI, SDI, Reset, PSL, LCV, INVSH, Pattern Error)– Framed BER measurement– Round Trip Delay RTD Measurement (min, avg, max)
LINK?EthernetHDLC
BBU
BBU
SFP
BBU
CPRI link configuration CPRI link status
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MT1000A Tester for TransportOTN /CPRI Product Features
Several vendors use Optical Transport Network (OTN) to transport CPRI .Specific OTN tests are required at this layer:
– OTN Alarm/Error detection– L1 Unframed BER measurement using CPRI client signals
Copyright© ANRITSU31
Agenda
• Introduction• C-RAN Technology Overview• Tests required and solutions for CPRI Network
– Optical Test– CPRI Test– RFoCPRI Test
• Summary
MT1000A/MT1100A Training FY 2015
32 Copyright© ANRITSU
Typical test configuration for CPRI RF testing
80% / 20%or
50% / 50%
or
CPRI link
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CPRI based measurements
• Differences with Traditional RF
• Configuring CPRI Link
RF CPRI
Analog Digital
Absolute Measurements Relative Measurements
dBm dB
Specific Center Frequency Base Band 0 Hz
Absolute Power levels Relative Power Levels
Full Span capable Max Span: Carrier BW +50%
CPRI Link
Key CPRI Parameters
Line Rate (rates 1 to 7 supported)
AxC (Antenna Container: 0 to 10)
CPRI BW (Bandwidth of LTE carrier)
IQ Bit Width (10, 12, 15, 16)
Reserve / Stuffing Bits (0 to 10)
Aggregation (On / Off)
Note: Configurations can be different on UL & DL
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CPRI digital filtering - Limitations for Interference Hunting
LTEUplink
Nearby Transmitter
Pre-filter Frequency Range
Digital Filter
LTEUplink
Carrier BW + 50%
Traditional filtering
CPRI Digital Filter Only Tx Carrier IQ
CPRI based Interference Testing
In-Band only
CPRI Link
RRH
BBU
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How to connect the instrument to the RRH/BBU
BBU
Optical TAP
A B AB
BBU
RRU
BBU
RRU
BBU
BTS
Mas
ter
RRU
Normal RRU to BBUConnection
Measures with Live Traffic
RRU
SFP
SFP
SFP
BBU
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Layer 2 Alarms
BTS Master (2 SFP Ports)E series (1 SFP Port) MT1000A (2 SFP Ports)
SFP monitoring and alarm monitoring
Loss of Signal (LOS)Loss of Frame (LOF)LSS (Loss Sequence Synchronization)
Loss of Signal (LOS)Loss of Frame (LOF)LSS (Loss Sequence Synchronization)
Loss of Signal (LOS)Loss of Frame (LOF)LSS (Loss Sequence Synchronization)
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SFP Data
BTS Master (2 SFP Ports)E series (1 SFP Port) MT1000A (2 SFP Ports)
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CPRI spectrogram screen
• Spectrum and / or Spectrogram is useful for intermittent signals
• Use the spectrogram to look for signals that change over time• Unstable regarding frequency
and / or level
• Passive Intermodulation
• From a cell phone booster with insufficient input to output isolation
• Common consumer grade equipment issue
• Temperature sensitive
• Sensitive to changing reflections
• People
• Cars
• etc…
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CPRI data
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Agenda
• Introduction• C-RAN Technology Overview• Tests required and solutions for CPRI Network
– Optical Test– CPRI Test– RFoCPRI Test
• Summary
MT1000A/MT1100A Training FY 2015
41
Summary
New challenges in the telecoms, the Mobile Network architecture will migrate using new technologies such as C-RAN and CPRI.
RF signal digitized as close as possible to RF antenna. The framed signal transmits information into the FrontHaul, BackHaul, and Core networks.
New network equipment to be installed for Mobile networks, vendors and operators have already done some trials.
Installation & Maintenance of these new network technologies require new procedures and testers.
Anritsu, leader in the instrumentation market, offers testers for optical link, CPRI protocol and RFoCPRI.
42| CONFIDENTIAL |
PM1-1SN150067-00
OTDR +CPRIOTDR +CPRI+ RFoCPRI Test
Anritsu is the only supplier that can cover all mobile network testing needs.Mobile Network Market
Network MasterPTP/SyncE
RFoCPRI +RFoCPRI +RF Test
NetworkMaster
BTSMaster
Questions?
END
Additional information
46 Copyright© ANRITSU| CONFIDENTIAL |
L1 Inband protocol• LOS
– Detection: 8B/10B or 64B/66B line coding errorsor low optical power level
– Action: Change to state “B” of the start-up process
• LOF– Detection: Hyperframe alignment isn’t possible– Action: Change to state “B” of start-up
process (RRH prevent emission “recommended”)
• Reset– Action: Sent from any master to
slave port, forwarded from slave to master (daisy chained) Extract from Figure 30
in CPRI Specification V6.1: Start-up states
and transitions
Standby
L1 synchronization
Protocol setup
C/M plane (L2+) setup
Interface and vendor specific negotiation
Operation
Passive link
No C&M
C&M proposed
A
B
C
D
E
F
G
State
47 Copyright© ANRITSU| CONFIDENTIAL |
L1 Inband protocol• RAI
– Detection: Any CPRI transceiver errors LOS, LOF etc.
– Action on Remote: Change to state “B” of start-up process (RRH prevent emission “recommended”)
• SDI– Detection: Near end informing far end
equipment – link must not be used for any Service Access Points
– Action on Remote: Far end must not use the link anymore (RRH prevent emission “recommended”) Extract from Figure 30
in CPRI Specification V6.1: Start-up states
and transitions
Standby
L1 synchronization
Protocol setup
C/M plane (L2+) setup
Interface and vendor specific negotiation
Operation
Passive link
No C&M
C&M proposed
A
B
C
D
E
F
G
State