Tài liệu The Synchronisation of Telecommunications Network doc

Issue 05/01 Slide 1.1 http://www.oscilloquartz.com Oscilloquartz SA The Synchronisation of Telecommunications Networks Issue 05/01 Slide 1.2 http://www.oscilloquartz.com Oscilloquartz SA Contents Contents I. The Need for Synchronisation II. Characterizing Synchronisation Quality III. Synchronisation Distribution: General Principles IV. Synchronisation Distribution: SDH/SONET-based Solution 1. Elements 2. Architecture 3. Synchronisation Status Message (SSM) V. Synchronisation Distribution: GPS-based and MixedSolution I. The Need for Synchronisation II. Characterizing Synchronisation Quality III. Synchronisation Distribution: General Principles IV. Synchronisation Distribution: SDH/SONET-based Solution 1. Elements 2. Architecture 3. Synchronisation Status Message (SSM) V. Synchronisation Distribution: GPS-based and MixedSolution Issue 05/01 Slide 1.3 http://www.oscilloquartz.com Oscilloquartz SA Contents Contents VI. Synchronisation Distribution: From Co-operating Network VII. Summary on Standards VIII. How to Synchronize Mixed Technology Networks 1. Mixed Technology Network Example 2. SDH and SONET Networks 3. The Public Switched Telephony Network VI. Synchronisation Distribution: From Co-operating Network VII. Summary on Standards VIII. How to Synchronize Mixed Technology Networks 1. Mixed Technology Network Example 2. SDH and SONET Networks 3. The Public Switched Telephony Network Issue 05/01 Slide 1.4 http://www.oscilloquartz.com Oscilloquartz SA Contents Contents VIII. How to Synchronize Mixed Technology Networks (cont ’d) 4. ATM Networks 5. Optical Networks 6. GSM and UMTS-FDD Radio Access Networks 7. cdmaOne and cdma2000 Radio Access Networks VIII. How to Synchronize Mixed Technology Networks (cont ’d) 4. ATM Networks 5. Optical Networks 6. GSM and UMTS-FDD Radio Access Networks 7. cdmaOne and cdma2000 Radio Access Networks Issue 05/01 Slide 1.5 http://www.oscilloquartz.com Oscilloquartz SA Abbreviations Abbreviations » ADM Add Drop Multiplexer » ATM Asynchronous Transfer Mode » BITS Building Integrated Timing Supply » bit/s bits per second 1kbit/s = 1,000 bits/s 1Mbit/s = 1,000,000 bits/s 1Gbit/s = 1,000,000,000 bit/s » CBR Constant Bit Rate » CDV Cell Delay Variation » DNU Do Not Use » DXC Digital Cross-Connect » f frequency » FIFO First-In First-Out » GPS Global Positioning System » GUI Graphical User Interface » HSC High Stability Clock » ADM Add Drop Multiplexer » ATM Asynchronous Transfer Mode » BITS Building Integrated Timing Supply » bit/s bits per second 1kbit/s = 1,000 bits/s 1Mbit/s = 1,000,000 bits/s 1Gbit/s = 1,000,000,000 bit/s » CBR Constant Bit Rate » CDV Cell Delay Variation » DNU Do Not Use » DXC Digital Cross-Connect » f frequency » FIFO First-In First-Out » GPS Global Positioning System » GUI Graphical User Interface » HSC High Stability Clock » Hz Hertz (cycles per second) 1mHz = 0.001Hz 1 µHz = 0.000001Hz » ITU International Telecommunications Union » k kilo = 1,000 » LOS Loss Of Signal » LT Line Terminal » MTIE Maximum Time Interval Error » NE Network Element » OC-N Optical Carrier level N » OS Operating System » p pointer » PABX Private Automatic Branch Exchange » PDH Plesiochronous Digital Hierarchy » PEC Plesiochronous Equipment Clock » PLL Phase Locked Loop » Hz Hertz (cycles per second) 1mHz = 0.001Hz 1 µHz = 0.000001Hz » ITU International Telecommunications Union » k kilo = 1,000 » LOS Loss Of Signal » LT Line Terminal » MTIE Maximum Time Interval Error » NE Network Element » OC-N Optical Carrier level N » OS Operating System » p pointer » PABX Private Automatic Branch Exchange » PDH Plesiochronous Digital Hierarchy » PEC Plesiochronous Equipment Clock » PLL Phase Locked Loop Issue 05/01 Slide 1.6 http://www.oscilloquartz.com Oscilloquartz SA Abbreviations Abbreviations » PRC Primary Reference Clock » ps/km/°C pico seconds per kilometre per degree centigrade » QL Quality Level » QOS Quality Of Service » s second 1ms = 0.001s » SASE Stand Alone Synchronous Equipment » SD Synchronisation Distribution » SDH Synchronous Digital Hierarchy » SC SONET Clock » SEC Synchronous Equipment Clock » SETG Synchronous Equipment Timing Generator » SETS Synchronous Equipment Timing Source » sin Sine function » SOH Section OverHead » SONET Synchronous Optical Network » SRTS Synchronous Residual Time Stamp » PRC Primary Reference Clock » ps/km/°C pico seconds per kilometre per degree centigrade » QL Quality Level » QOS Quality Of Service » s second 1ms = 0.001s » SASE Stand Alone Synchronous Equipment » SD Synchronisation Distribution » SDH Synchronous Digital Hierarchy » SC SONET Clock » SEC Synchronous Equipment Clock » SETG Synchronous Equipment Timing Generator » SETS Synchronous Equipment Timing Source » sin Sine function » SOH Section OverHead » SONET Synchronous Optical Network » SRTS Synchronous Residual Time Stamp » SSM Synchronisation Status Message » SSU Synchronisation Supply Unit » STM-N Synchronous Transport Module level N » STS-N Synchronous Transport Signal level N » TF Transfer Function » TIE Time Interval Error » TS0 Time Slot Zero » VBR Variable Bit Rate » VCO Voltage Controlled Oscillator » VC Virtual Container » VT Virtual Tributary » VTG Virtual Tributary Group » UN Undefined » W Wander » w radians per second » d variation » SSM Synchronisation Status Message » SSU Synchronisation Supply Unit » STM-N Synchronous Transport Module level N » STS-N Synchronous Transport Signal level N » TF Transfer Function » TIE Time Interval Error » TS0 Time Slot Zero » VBR Variable Bit Rate » VCO Voltage Controlled Oscillator » VC Virtual Container » VT Virtual Tributary » VTG Virtual Tributary Group » UN Undefined » W Wander » w radians per second » d variation Issue 05/01 Slide 1.7 http://www.oscilloquartz.com Oscilloquartz SA The Need for Synchronisation The Need for Synchronisation Issue 05/01 Slide 1.8 http://www.oscilloquartz.com Oscilloquartz SA Frequency synchronisation Frequency synchronisation System A t t Clock signal of system A Clock signal of system B System B T A = 1 / f A T B = 1 / f B f A = f B Issue 05/01 Slide 1.9 http://www.oscilloquartz.com Oscilloquartz SA Phase synchronisation Phase synchronisation System A t t Clock signal of system A Clock signal of system B System B ! !! Issue 05/01 Slide 1.10 http://www.oscilloquartz.com Oscilloquartz SA Time synchronisation Time synchronisation System A t t Time signal of system A Time signal of system B System B 14/01/00 08:34:56 14/01/00 08:34:57 14/01/00 08:34:55 14/01/00 08:34:55 14/01/00 08:34:56 14/01/00 08:34:57 [...]... Unit http://www.oscilloquartz.com Oscilloquartz SA Physical synchronisation network : 2 » Not every system in the network can have a direct connection to the master network clock » Therefore the telecommunication systems are synchronised in chains or trees » Each system clock is the master clock of the subordinate system clocks slaved to it » The chains can be very long or very short Issue 05/01 Slide... Definition of jitter : ITU-T Rec G.810  The short term variations of the significant instants of a digital signal from their reference positions in time  Greater than 10Hz in modulation frequency Ideal Jittered Sampling (reading) points Issue 05/01 Slide 1.25 http://www.oscilloquartz.com Oscilloquartz SA Definition of wander : ITU-T Rec G.810 · The long term variations of the significant instants of a... Oscilloquartz SA Synchronisation between telecommunication systems : 2 » The slave system continually adjusts its own clock to the incoming signal » The incoming signal contains both the clock and data information » Therefore both the master and slave systems have the same transmit and receive rates » There are no slips Issue 05/01 Slide 1.31 http://www.oscilloquartz.com Oscilloquartz SA Synchronisation. .. Inter -network synchronisation Network A System data atomic clock Issue 05/01 Slide 1.32 transmission link data Network B System data atomic clock http://www.oscilloquartz.com Oscilloquartz SA Synchronisation between telecommunication systems : 4 » Each system is synchronised by separate atomic clocks » The atomic clocks have nearly the same free running frequency » There is little difference between the. .. Frequency Issue 05/01 Slide 1.22 http://www.oscilloquartz.com Oscilloquartz SA Characterizing Synchronisation Quality Issue 05/01 Slide 1.23 http://www.oscilloquartz.com Oscilloquartz SA Definition of jitter : ITU-T Rec G.810  The short term variations of the significant instants of a digital signal from their reference positions in time  Greater than 10Hz in modulation frequency Ideal Jittered Sampling... both ends » The slip rate is only one in every 72 days » Totally acceptable for inter-national and intra-national traffic of every kind of services Issue 05/01 Slide 1.33 http://www.oscilloquartz.com Oscilloquartz SA Physical synchronisation network : 1 mastermaster-slave chains SSU SEC SDH Equipment Clock PRC PRC = Primary Reference Clock Telecom equipment clocks Issue 05/01 Slide 1.34 Synchronisation. .. - νNOM νNOM where ν(t) = actual frequency of the signal νNOM = specified nominal frequency Issue 05/01 Slide 1.28 http://www.oscilloquartz.com Oscilloquartz SA Synchronisation Distribution: General Principles Issue 05/01 Slide 1.29 http://www.oscilloquartz.com Oscilloquartz SA Synchronisation between telecommunication systems : 1 » Master-slave intra -network synchronisation data Master System transmission... http://www.oscilloquartz.com Oscilloquartz SA SDH/SONET Transport Networks: Nominally Synchronous Multiplexing 63 x E1 1 x STM-1 1 2 OH 1 2 63 Multiplexer 63 Issue 05/01 Slide 1.18 http://www.oscilloquartz.com Oscilloquartz SA Wander induced by pointer activity TIE of E1 signal TIE of E1 signal PRC t E1 t NE ADM NE E1 ADM NE SDH/SONET Network Synchronisation distribution trails affected by wander Issue... Issue 05/01 Slide 1.19 http://www.oscilloquartz.com Oscilloquartz SA SDH/SONET Transport Networks: Nominally Synchronous Multiplexing » PDH tributaries need not be synchronous with the SDH aggregates (pointer technique) » However, relative wander between the incoming PDH tributary and the SDH aggregates induce wander on the outgoing PDH tributary (pointer adjustments!) » If excessive, this tributary wander...Where do we need synchronisation? Three examples » Public Switched Telephone Networks » SONET and SDH transport networks » Cellular mobile telecom networks Issue 05/01 Slide 1.11 http://www.oscilloquartz.com Oscilloquartz SA Public Switched Telephone Network: Synchronous Multiplexing 30 x 64 kbit/s 1 x 2.048 Mbit/s 1 2 1 2 30 Multiplexer . Oscilloquartz SA The Synchronisation of Telecommunications Networks Issue 05/01 Slide 1.2 http://www.oscilloquartz.com Oscilloquartz SA Contents Contents I. The Need. Architecture 3. Synchronisation Status Message (SSM) V. Synchronisation Distribution: GPS-based and MixedSolution I. The Need for Synchronisation II. Characterizing Synchronisation