microwave clock transmission solutions
DESCRIPTION
Intended for the field product managers to learn and make clock transmission solutions, and to communicate with customers.TRANSCRIPT
HUAWEI TECHNOLOGIES CO., LTD.
www.huawei.com
Huawei Confidential
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23/4/8
Transmission Network Marketing Support Department
Microwave Clock Transmission Solutions
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Document DescriptionDocument Name Microwave Clock Transmission Solutions
Objective Intended for the field product managers to learn and make clock transmission solutions, and to communicate with customers.
Intended Audience Sales personnel and marketing personnel
Content This document describes the meaning and principle of microwave clock synchronization, clock transmission capability, and common clock synchronization solutions.
Usage GuideVersion Information
Version Date Prepared by Approved by Issued by
V1.00 June 2010 Huang Zengsong, Zong Yong Wang Xiaozhong
Transmission Network Marketing
Support Department
V1.10 Nov 2010 Huang Zengsong Wang XiaozhongTransmission
Network Marketing Support
Department
Please delete this slide
before presentation!
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 3
Version Date Modification Prepared by Approved by Issued by
V1.2 Jun 2011Modify the roadmap of
1588V2Huabinshan Zhou xiao
Transmission Network
Marketing Support
Department
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ContentsContents
33 Microwave Clock Transmission Microwave Clock Transmission SolutionsSolutions
11 Why Is the Clock Synchronization Why Is the Clock Synchronization NecessaryNecessary
22 Microwave Clock Transmission Microwave Clock Transmission ModesModes
44 FAQFAQ
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 5
Concepts of Clock SynchronizationConcepts of Clock Synchronization
What is a clock?A clock is a device that generates time signals. Clock signals involve the reference specifications such as frequency, period, jitter, and wander.
What is synchronization? Synchronization refers to that two signals appear or disappear in the same state at the same moment.
Clock synchronization refers to that all the devices on the network operate at the same rate.
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Modes of Clock SynchronizationModes of Clock Synchronization
Frequency synchronization The signals remain a relative relationship in
frequency and phase. The corresponding valid instances appear at
the same average rate. As shown in Figure 1, clock B is six hours later
than clock A. Clock synchronization generally refers to
frequency synchronization.
Time synchronization The signals remain a consistent
relationship in frequency and phase. The phase of a clock is expressed in value,
that is, moment. As shown in Figure 2, clock B and clock A
remain the same in time at any moment.
Frequency synchronization
Clock A
Clock B
Clock A
Clock B
Figure 1
相 位 同 步
Figure 2
Time synchronization
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What Are the Impacts When the What Are the Impacts When the Clocks Are not Synchronized?Clocks Are not Synchronized?
Data:Characters in fax application are missed. The Internet is offline frequently.Mosaic images occur in the video services
Voice application:Calling failsconversation is not consecutive, and even crosstalk occurs. In the case of cross-boundary handover or dual-band handover, handoff occurs or the communication is unilateralism available.
Frequency Deviation Slips/per day
10E -11 0.007
10E -9 0.69
10E -7 69.1
10E -6 691.2Clocks not
synchronized
Impact of slip accumulation
Slip
Communication quality is
degraded !
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Requirements of Mobile Requirements of Mobile Communication for Clock Communication for Clock SynchronizationSynchronization
Mobile Communication
Technology
Requirement for Frequency
Synchronization
Requirement for Time
Synchronization
GSM 0.05 ppm NA
WCDMA 0.05 ppm NA
TD-SCDMA 0.05 ppm 3 us
CDMA2000 0.05 ppm 3 us
WiMax FDD 0.05 ppm NA
WiMax TDD 0.05 ppm To be determined
LTE 0.05 ppm 1.66 us (temporarily)
The requirements for clock synchronization are higher and higher!
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ContentsContents
33 Microwave Clock Transmission SolutionMicrowave Clock Transmission Solution
11 Why Is the Clock Synchronization Why Is the Clock Synchronization NecessaryNecessary
22 Microwave Clock Transmission Microwave Clock Transmission ModeMode
44 FAQFAQ
Comparison of Application ScenariosComparison of Application Scenarios
Overview of Common Clock Transmission Overview of Common Clock Transmission ModesModesIntroduction to Microwave Introduction to Microwave ClocksClocks
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Overview of Common Clock Transmission Overview of Common Clock Transmission ModesModes
Physical synchronization: a clock synchronization mode in which clock information is saved in a service stream.
Packet synchronization: a clock synchronization mode in which clock information is saved in a service packet.
Packet synchronization and time synchronization future-proof the clock synchronization technology.
Frequency synchronizationTime synchronization
Not supported by RTN equipment
Packetsynchronizatio
n 1588v
2
Physical synchronizatio
n SyncEth GPS
1588 ACR
CES
NTP
PDH/SDH
Supported by RTN equipment
Supported by wireless equipment
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
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PDHPDH Clock SynchronizationClock Synchronization
Transmit end: E1 signals are loaded into container C through bit adjustment, multiplexed into high-speed signals, and sent out at the system clock frequency f at the transmit end. (On the OptiX RTN equipment , the E1 retiming function needs to be enabled on the part as shown in the figure.)
Receive end: E1 signals are demultiplexed from container C by eliminating bit adjustment. The features of E1 signals remain the same. The OptiX RTN equipment extracts and traces E1 clocks to achieve clock synchronization , as shown on the dotted-line part.
Advantages: The principles and technologies are simple, facilitating the transparent transmission of clocks.
Disadvantages: Multiplexing and demultiplexing cause signal deterioration, which affects the transmission of high traffic.
Note: The traditional PDH network is a pseudo – synchronous network. It does not need to extract clocks or support the E1 retiming function.
High-speed signal
NE A NE B
fSystem clock unit
Service stream bearer clock
E1 Container C E1Container C
fSystem clock unit
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
High-speed signal
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SDHSDH Clock SynchronizationClock Synchronization
Container Vc Container Vc
NE A NE B
fSystem clock unit
Service stream bearer clock
Service
Service
System clock unit f
Transmit end: Signals are loaded into container Vc, and sent out at the system clock frequency f at the transmit end. The STM-N bears the clock signal f.
Receive end: The clock signal f is recovered from the STM-N services, and sent to the system clock unit. The signals are considered as the system clock of the local NE and send out (as shown on NE A) to achieve the frequency synchronization between NE A and NE B.
Advantages: This technology is widely used and can meet the synchronization requirements of the SDH transmission network.
Disadvantages: The precision of the SDH clock synchronization only reach the millisecond level.
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
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Synchronous EthernetSynchronous Ethernet
Transmit end: The Ethernet interface sends out Ethernet services at the system clock frequency f through the PHY chip. The service stream bearers the clock signal f.
Receive end: The clock signal f is recovered from the STM-N services, and sent to the system clock unit. The signals are considered as the system clock of the local NE and send out (as shown on NE A) to achieve the frequency synchronization between NE A and NE B.
Advantages: This technology is widely used and can meet the synchronization requirements of the Ethernet transmission network.
Disadvantages: The precision of the SDH clock synchronization technology is not high, and can only reach the millisecond level.
Note: The processing of synchronous Ethernet is similar to the processing of the SDH synchronization. The difference is that the service stream is the Ethernet service stream but not the STM-N service stream.
Ethernet interface
NE A NE B
f
System clock unit
Service stream bearer clock
Data service
Data service
System clock unit
f
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
Ethernet interface
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IEEE 1588 V2 (Clock Architecture)IEEE 1588 V2 (Clock Architecture)
TCPrimary time
input
BC-11 2 3S M M
OC-1M
BC-21 2 3S M M
S
TC TCTC
BC: boundary clockOC: ordinary clockTC: transparently transmitted clock
SOC-2
OC-4M : master clockS: slave clock
OC model: only one port supports the transmission and extraction of IEEE 1588 V2 packets, and can either be the source or sink of the packets.
BC model: multiple ports support the IEEE 1588 V2 packets. To be specific, one port extracts and terminates the IEEE 1588 V2 packets, and the other ports generate and send out the new IEEE 1588 V2 packets. The BC contains the source and sink of the IEEE 1588 V2 packets.
TC model: processes the delay and transparently transmits clocks. The model does not extract and recover clocks.
Two NEs perform the relevant calculation based on the time stamps in the packets to achieve time synchronization.
SOC-3
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
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IEEE 1588 V2IEEE 1588 V2 (Master and Slave Clock (Master and Slave Clock Synchronization)Synchronization)
Delay request packet
Synchronization packet
Delay response packet
t1 , t2
t1 , t2 , t3
t1 , t2 , t3 ,t4
t1
t4
t2t3
Transmit end Receive end
△t1
△t2
The master clock transmits the synchronization packet at the moment t1, and the slave clock receives the packet at the moment t2 and obtains the time △t1.
The slave clock transmits the delay request packet at the moment t3, and the master clock receives the packet 2 at the moment t4 and obtains the time △t2.
Compute the trail delay and offset, and correct the time of the slave clock.Delay = (△t1 + △t2)/2 Offset = (△t1 - △t2)/2
Advantage: supports time synchronization, and is slightly associated with the PSN. The packets are transmitted independently, which is irrelevant to service transmission.
Disadvantage: All the equipment on the link needs to support the IEEE 1588 V2 protocol.
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
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1588 ACR1588 ACR
Transmit end: transmits the synchronization packets 1, 2, and 3 at the frequency f with time stamps t1, t1', and t1'' respectively.
Receive end: receives the synchronization packets 1, 2, and 3, and records the arrival times t2, t2', and t2''. Due to the impact of different delays, △t1, △t2, and △t3 may be different. However, the received end adds different weights for the time stamps to achieve frequency synchronization.
Advantage: The clock synchronization is of good quality, and the protocol is standardized to support the interconnection of equipment from different vendors.
Disadvantage: only supports frequency synchronization but not time synchronization, and is easily affected by the PDV.
synchronization packet 1
t1 , t2
t1 ’ , t2 ’
t1’’ , t2 ’’
t1
t1 ’’
t2
t2 ’
Transmit end Receive end
△t1
△t2t1 ’
t2 ’’
synchronization packet 2
synchronization packet 3
△t3
f fsynchronizatio
n packet N
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
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GPSGPS
The global positioning system (GPS) is operated by the astronomical observatory of the U.S navy. As a precise satellite-based global navigation and location system, the GPS is composed of 24 communications satellites, three of which work as standby ones. The GPS can provide high precision clocks to the BTS, NodeB, or BITS. Advantage: the clock synchronization is of good quality, and time synchronization is
supported. Disadvantage: is costly and cannot be widely deployed.
GPS satellite
BITS
11111Costly
deployment
NodeB/BTS
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
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Comparison Between Synchronization Comparison Between Synchronization TechnologiesTechnologiesSynchronization Technology
Frequency Synchronization
Time Synchronizati
on
Application Scenario
PDH √ X
1.The PDH network needs to be synchronized.2.The network provides PDH service interfaces only.3.The service needs to traverse the third-party PDH
and SDH lines.
SDH √ X 1.The SDH network needs to be synchronized.2.The network provides SDH service interfaces only.
Synchronous Ethernet √ X
1. PSN2. The network provides Ethernet service interfaces
only.
IEEE 1588 ACR √ X1.PSN2.The services need to transparently traverse the
third-party PSN.
IEEE 1588 V2 √ √ The network requires time synchronization.
GPS √ √ BITS and base stations that require high precision clocks from the GPS.
Microwave clockMicrowave clockOverviewOverview Application scenarioApplication scenario
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NodeB/BTSE1/FE/GE/external clock interface
The OptiX RTN equipment supports the transmission and reception of clocks at the slave clock interface, service interface, and air interface.
In actual networking, multiple clock bearer modes can be configured at the same time.
Air interface
External clock interface
Stm-1/E1/GE /FE service interface
Clock Bearer ModeClock Bearer ModeWith 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
3
2
1 BITS
RTNRTN
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ContentsContents
33 Microwave Clock Transmission Microwave Clock Transmission SolutionsSolutions
11 Why Is the Clock Synchronization NecessaryWhy Is the Clock Synchronization Necessary
22 Microwave Clock Transmission Microwave Clock Transmission ModesModes
44 FAQFAQ
Network Consisting of the OptiX RTN and Third-party Network Consisting of the OptiX RTN and Third-party EquipmentEquipment
Design PrinciplesDesign Principles
Typical ScenariosTypical Scenarios
Network Consisting of the OptiX RTNNetwork Consisting of the OptiX RTN Equipment onlyEquipment only
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Clock Bearer Technology(Except Clock Bearer Technology(Except 900R3)900R3)
Type/Version 620R1/R2
620R3/R5 605R1 605R3/
R5 900R1 900R2
Service interfa
ce
SDH √ √ × × √ √
E1
Transparent
transmission
√ √ √ √ × √ Retiming √ √ × × √ √
ETH
Synchronous Ethernet × √ × √ √ √
1588V2 × × × × √ × 1588ACR × × × × √ ×
Air interface √ √ × √ √ √ External clock √ √ × × √ √ Two clock transmission modes are available for E1 services:
1. Clock transparent transmission: Transmitted E1 clocks are irrelevant to the equipment.
2. Retiming: Transmitted E1 clocks are equipment clocks.
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Clock Bearer Technology (RTN900R3)Clock Bearer Technology (RTN900R3)
Type/Version900R3C00(2011Q
1)900R3C02(2011Q2
)910 950/980 910 950/980
Service
interface
SDH √ √ √ √
E1
Transparent
transmission
√ √ √ √ Retiming √ √ √ √ CES ACR √ √ √ √
ETH
Synchronous
Ethernet√ √ √ √
1588V2 √ × √ Hardware ready1588ACR √ × √
Air interface √ √ √ √ External clock √ √ √ √
With 3rd-PartyWith 3rd-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Clock transmission capability: m1*k1 + m2*k2+……<=1Note: m1 and m2 are the hop counts of the link IF boards, and k1 and k2 are the transmission capability coefficients of the IF board in the corresponding modes.
Equipment Series IF Board Clock Type
Transport Capability
Coefficient kHop Count Supported Remarks
RTN 620
IF0 E1 0.1 10IF1 E1/STM-1 0.1 10 IFX E1 0.1 10
IFH2Transparently transmitted E1 0.1 10 System clock/Synchronous Ethernet/Retiming E1 0.05 20
RTN 605
1A/1B/2B Transparently transmitted E1 0.1 10 1F/2F Transparently transmitted E1 0.1 10 1D/2D/1E/2E Transparently transmitted E1/Synchronous
Ethernet 0.0625 16
RTN 950/910
IFE2 Transparently transmitted E1 0.1 10
IF1 System clock/Synchronous Ethernet/Retiming E1 0.05 20
IFU2Transparently transmitted E1 0.1 10 Supported by only the
OptiX RTN 900 V100R002System clock/Synchronous Ethernet/Retiming E1 0.05 20
IFX2Transparently transmitted E1 0.1 10 Supported by only the
OptiX RTN 900 V100R002System clock/Synchronous Ethernet/Retiming E1 0.05 20
Clock Transmission CapabilityClock Transmission CapabilityWith 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Clock InjectionClock Injection
Clock input point Clock signal trail
Chain network: The length of the radio link whose clock transmission capability is insufficient is L, and the clock transmission capability is N.1. 0 < L < N. The clock is injected at an upstream node.2. N =< L < 2N. The clock is injected at an intermediate node.
Star network: The clock is injected at a hub node.
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
Clock input Clock inputClock input
Clock injection at an upstream
node
Clock injection at an intermediate
node
Clock injection at a
hub node
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Injecting the Clock from the BITS to the Injecting the Clock from the BITS to the OptiX RTN EquipmentOptiX RTN Equipment
A
BSC/RNC
E1
B
NodeB/BTS
E1/FE
Injecting the clock from the
BITS
The clock is transmitted through the external clock interface/E1, Ethernet, or SDH service interface and the air interface.
Note: When the clock transmission capability of the OptiX RTN equipment is insufficient, the clock needs to be injected from the BITS for clock compensation.
BITS
The clock is transmitted through the OptiX RTN
equipment
Injecting the clock into the base
station
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Injecting the Clock from the Injecting the Clock from the Transmission Equipment to the OptiX Transmission Equipment to the OptiX RTN EquipmentRTN Equipment
A
BSC/RNC
E1
B
NodeB/BTS
E1/FE
Injecting the clock from the transmission
equipmentThe clock is transmitted through the external clock interface/E1, Ethernet, or
SDH service interface and the air interface.Note: When the clock transmission capability of the OptiX RTN equipment is
insufficient, the clock needs to be injected from the BITS equipment for clock compensation.
BITS
The clock is transmitted through the OptiX RTN
equipment
Injecting the clock into the base
station
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Scheme 1 Clock Re-injectionScheme 1 Clock Re-injection
MUXThird party
MUX
B A
BSC/RNC
E1
C
FE
NodeB
NodeB/BTS
E1/FE
E1/STM-1/GEE1/STM-1/GE
After the clock traverses the leased line, the BITS re-injects the clock into the OptiX RTN equipment.
After the clock is re-injected, the microwave clock transmission solution is as on a network consisting of the OptiX RTN equipment only.
Re-injecting the clock from the
BITS
Injecting the clock from the
BITS
Network consisting of the OptiX RTN
equipment only
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Scheme 2 Tracing the Clock from the Scheme 2 Tracing the Clock from the Third-Party EquipmentThird-Party Equipment
E1
C
FE
NodeB
NodeB/BTS
E1/FE
MUXThird party
MUX
B A
BSC/RNC
E1/STM-1/GEE1/STM-1/GE
Clock injection modes: injection through a service interface and injection through an external clock interface
Disadvantages: (1) The quality of the third-party clock is hard to be evaluated; (2) When jitters or degrades occur in the third-party clock the clock quality of the OptiX RTN equipment is affected, and the services may be faulty. The fault is hard to be located.
Tracing the clock from the BITS
equipment
Tracing the clock from the third-party
equipment
Not recommended
Network consisting of the OptiX RTN
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Scheme 3 Transparently Transmitting Scheme 3 Transparently Transmitting the Clock Through the Third-Party the Clock Through the Third-Party NetworkNetwork
MUXThird party
MUX
B A
BSC/RNC
E1
C
FE
NodeB
NodeB/BTS
E1/FE
E1/STM-1/GE
E1/STM-1/GE
Prerequisite: The third-party network provides the channel for transparently transmitting clocks (though a service channel, for example) so that network A and network C can be synchronized.
Supported services: E1, STM-1, and IP-based services on the third-party network. Clock synchronization mode: After the clock traverses the third-party network, only frequency synchronization
is supported. Computation of clock transmission capability: When the quality of the clock after traversing the third-party
equipment meets G.823 sync, the clock transmission capability needs to be multiplexed by 0.7; When the quality of the clock after traversing the third-party equipment meets G.823 Traffic, the clock transmission capability needs to be multiplexed by 0.1.
Tracing the clock form the
BITS
Transparently transmitting the clock
through the service channel
Extracting the clock of network A from the
service
Network consisting of the
OptiX RTN
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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1. E1 Leased Line1. E1 Leased Line
Network A: When E1 retiming is used, the network system clock is injected into the E1 service (recommended).
Network B: The E1 clock transparent transmission function needs to be supported (consult the third-party network supplier).
Remark: if the E1 retiming function is also enabled on network B, the E1 clock cannot be transparently transmitted.
Network C: The E1 clock is extracted.
MUXThird party
MUX
B A
BSC/RNC
E1 E1
Network consisting of the OptiX RTN
Injecting the clock into the
E1 service
Transparently transmitting the E1
service
Extracting the clock from the
E1 service
E1
C
FE
NodeB
NodeB/BTS
E1/FE
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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2. 2. STM-1STM-1 Leased LineLeased Line
Third party
MUX
B
E1
C
Stm-1
E123
NodeB/BTS
E1/FE RTNRouter
BTS
1
Stm-1 Stm-1
A
RNC
Retiming E1 services, looping back the E1 services and cross-
connecting them to the VC-12s in the STM-1
Adding an OptiX RTN device for
time extraction
Transparently
transmitting STM-1 services
Extracting the clock
from the E1 service
Network consisting of the
OptiX RTN
E1
Network A: ① The E1 service is looped back. The E1 retiming function is enabled and the system clock is re-injected. The E1 clock quality meets the requirement (recommended).
Network B: Transparently transmits STM-1 services. Network C: ② Adds the IDU 620/910, extracts the E1 clock by broadcasting cross-connections, and
transparently transmits the STM-1 service. ③ Extracts the clock from the E1 service and receives STM-1 services.
MUX
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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3. Ethernet Leased Line3. Ethernet Leased Line
The third-party PSN meets the following conditions:1. The clock performance cannot be affected by PDV caused by transmission over PSN. The PDV cannot exceed
±10 ms. 2. The PDV values within one second must be the minimum values. These values completely or basically comply
with normal distribution, and meet the requirement of 6σ < 20 us. Disadvantages:1. The PDV of the third-party network is hard to be evaluated, which may introduce risks to the clock quality.2. Only the OptiX RTN 900 V100R001that is not a mainstream product support the IEEE 1588 ACR function.
MUXThird party
MUX
B A
BSC/RNC
ETH ETH
Network consisting of the
OptiX RTN
Using the 1588ACR function to inject the
clock into the Ethernet service
Transparently transmitting the Ethernet service
Extracting the clock from the Ethernet
service
Not recommended
E1
C
FE
NodeB
NodeB/BTS
E1/FE
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Scenario 1 Transparently Transmitting Scenario 1 Transparently Transmitting STM-1 ServicesSTM-1 Services
Third party
MUX
B
E1
C
Stm-1
E123
E1/FE
NodeB/BTS
E1/FE
NodeB/BTS
OSN1500 OSN3500
Router
BTS
1
Stm-1 Stm-1
A
Scenario: Huawei's routers, OptiX OSN 3500, OptiX OSN 1500, OptiX RTN equipment, and third-party equipment construct the networks. The third-party network provides the STM-1 leased line.
Note: ① The E1 service is looped back. The E1 retiming function is enabled and the system clock is re-injected. The E1 clock quality meets the requirement (recommended). ② The added OptiX RTN NEs should be IDU 910/620 (the IDU 605 is not supported). The OptiX RTN NE trace the third-party clock.
RNC
Retiming E1 services, looping back the E1 services and cross-
connecting them to the VC-12s in the STM-1
Adding an OptiX RTN
device for time extraction
Transparently
transmitting the STM-1
service
Extracting the clock
from the E1 service
Network consisting of the OptiX RTN
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
MUX
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Scenario 2 Using the GPS Clock at the Base Scenario 2 Using the GPS Clock at the Base StationStation
Scenario: The OptiX RTN equipment and the third-party equipment construct networks, achieving clock synchronization between the RNC/BSC and the NodeB/BTS.
Note: The clock signal of the NodeB/BTS is obtained from the GPS. The OptiX RTN is not involved or need not be synchronized. ① After the clock traverses the third-party network or when the clock does not meet the requirement, the
clock mode is set to the free-run mode on the OptiX RTN equipment to provide the clock to the downstream NEs.
② Traces the clock that is in free-run mode on the OptiX RTN equipment.③ Not all the NodeB/BTS is capable of obtaining clocks from the GPS.
A
RNC/BSC
MUXThird party
MUX
BE1
C
NodeB/BTS
E1/FE
In free-run mode, providing the clock for the downstream OptiX RTN
equipment
BITS clock
Clock in free-run mode
BTS
123
Obtaining the GPS clock at the NodeB/BTS
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
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Scenario 3 IP Services without ClocksScenario 3 IP Services without Clocks
A
BSC/RNC
FE
NodeB/BTS
FE
FE
NodeB/BTS
B
① Externally connected to the GPS
② Connected to the external clock
interface
③ Idle E1 clock
①The base station transmits the framed E1 signal.②The received E1 service is looped back on the cross-connect unit, and is retimed for clock injection. ③The E1 clock is transmitted to the base station.
BTS
Scenario: The NodeB/BTS transmits all IP services. The OptiX RTN 600 or NodeB/BTS does not support synchronous Ethernet.
Note: In the case of scheme 1, note that not all the NodeB/BTSs are capable of obtaining clocks from the GPS. For details, contact the headquarters of the wireless product line.In the case of schemes 2 and 3, only the IDU 620/950/910 support the clock transmission through the external clock interface or E1 retiming function.
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 36
Scenario 4 Using the IP Clock Scenario 4 Using the IP Clock EquipmentEquipment
MUXThird party
MUX
BC3FE
NodeBFE
NodeB
OSN3500 Router
NodeB
1
A
RNC
IP clock
FE
In free-run mode, providing the clock to the
downstream RTN NEs
2
Injecting the clock from the
BITS to the RNC
Transmitting the 1588ACR clock packet in the
services
Extracting the IEEE
1588 ACR clock from
the FE service
Scenario: The OptiX RTN equipment and the third-party equipment construct networks. The NodeB transmits all IP-based services.
Note: The IP clock equipment is a clock source device developed by Huawei. The IP clock equipment transmits IEEE 1588 ACR clock packets to the NodeB to achieve clock synchronization (the OptiX RTN equipment cannot extract the clock packet).
Note: ① The IP clock equipment injects the IEEE 1588 ACR clock packet into the routers. The clock packet is carried in a independence the FE service. ② The PDV needs to be considered in the transmission of the IEEE 1588 ACR clock packet.
IP clock equipment
generates the 1588ACR clock
packet
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 37
Scenario 5 Using the Same Clock on Scenario 5 Using the Same Clock on the With 3-Partysthe With 3-Partys
E1
C
FE
NodeB
NodeB/BTS
E1/FE
NEC
Third party
NEC
B A
BSC/RNC
E1/STM-1E1/STM-1
OSN
Scenario: The OptiX OSN equipment, OptiX RTN equipment, and NEC's equipment construct the networks.
Disadvantages: (1) The quality of the third-party clock is hard to be evaluated; (2) When jitters or degrades occur in the third-party clock the clock quality
of the OptiX RTN equipment is affected, and the services may be faulty. The fault is hard to be located.
Tracing the clock from the BSC/ RNC
Tracing the OptiX OSN equipment clock
Tracing the NEC equipment clock
2 1
Not recommended
With 3-PartyWith 3-PartyDesign principleDesign principle Typical scenarioTypical scenarioRTN networkRTN network
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 38
ContentsContents
33 Microwave Clock Transmission Microwave Clock Transmission SolutionsSolutions
11 Why Is the Clock Synchronization Why Is the Clock Synchronization NecessaryNecessary
22 Microwave Clock Transmission Microwave Clock Transmission ModesModes
44 FAQFAQ
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 39
Restrictions on the Synchronous Ethernet Restrictions on the Synchronous Ethernet Feature Enabled on the OptiX RTN 600Feature Enabled on the OptiX RTN 600
Only the GE interface on the 605 1F/2F supports synchronous Ethernet.
Only the IFH2 board on IDU 620 supports synchronous Ethernet.Support the output and input.
The four Ethernet service interfaces on the 605 1E/2E supports synchronous Ethernet. The FEx2 interface supports the output.
The GEx2 interface supports the output and input.
The FEx3 interface does not support.The GE interface supports the output and
input.
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
Typical BITS of Huawei
Page 40
BITS ( Building Integrated Timing Supply), get clock signal from GPS or other clock source equipment , then provide the clock for other communication equipments. Huawei provide V3/V5/V6(T6020) BITS equipments , and recommend use Synlock V3/V6(T6020) in microwave solution.
Frequency synchronization100 frequency interfaces output Suit for big network
Frequency synchronization16 frequency interfaces output Suit for middle or small network
Frequency&phase synchronization ( 1588V2 )8/14 interfaces frequency /phase outputSuit for small network
recommendatory
Synlock V6 ( T6020 )
Synlock V3Synlock V5
recommendatory
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 41
Q: How does the third-party clock traverse a network consisting of the OptiX RTN equipment?
A: This is similar to the solution for the clock of the OptiX RTN equipment traversing the third-party network. Two factors need to be considered: (1) the bearer mode of the clock; (2) whether the clock meets the requirement of the third-party network after traversing a network consisting of the OptiX RTN equipment.
Q: Where can I obtain documents about Clock solutions except this slide? A: You can download the relevant documentation set from the 3ms website.
Document URL Link
White Paper on Clock Transmission Over Radio (Chinese) 3MS
White Paper on Clock Transmission Over Radio (English) 3MS
Thank youwww.huawei.com