Inter ernati national onal Pr Practi tice ce: : Ove vervi rview ew of the Techni hnical al Soluti tions ons Dr. Amr Ba Badawi awi Ex Pr Presid esiden ent, , Bo Board rd Mem ember ber NTRA Egy gypt pt
Broadband Speed International Definition New Speeds in action Technologies xDSL GPON
Overview The DSL technologies have evolved in terms of data rates, both in down and upstream. However, the current performance stretches the limits of the copper cable medium. xDSL datarates evolution Remarks >100 ADSL was the first Downlink (Mbps) technology that enabled data services via copper lines and achieved data 52 rates in the range of 6Mbps 24 ADSL2+ brings improvements in datarates 6 WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT (upt to 24Mbps) by increasing the amount of ADS ADSL2 VDS VDSL L + L 2 data carriers (and the used >100 frequency band) Uplink (Mbps) VDSL2 aggregate data rates in the range above100 Mbps by flexible bandwidth usage of up to 30 MHz 16 However, VDSL2 3 1 performance falls sharply if the cable is longer than 1 ADS ADSL2 VDS VDSL km and datarates will be L + L 2 comparable with ADSL2+ Pag e 3
Synergies with existing PSTN network The Outside plant does not need to change to support DSL services over legacy PSTN copper . The Outside Plant Architecture for DSL (no change) ISDN DSLAM Customer premise Distribution Point UNIs WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT Cabinet Main Distribution Frame building Primary Network Secondary Network DSL modem Pag e 4
xDSL types DSL technologies and standards differentiate between asymmetric, symmetric and very high speed flavors. Asymmetric DSL Symmetric DSL Very High Speed DSL ADSL uses high Down to Up- SDLS requires the whole VDSL currently forms the stream bandwidth ratios (1:10) frequency band of the copper leading edge of the xDSL which is ideal for client-server pair, i.e. no line sharing with technologies. applications. telephony takes place. Frequencies up to 30 MHz POTS/ISDN frequency Symmetrical behaviour is (similar to Fast Ethernet on band is not used by ADSL ideal for slow speed fixed CAT 5 cables) boost the line replacement, with bandwidth in Fast Ethernet- WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT Passive frequency filter SDSL being typically used like regions (> 100 Mbps) separate telephony from for business applications broadband High frequency damping on Channel bonding/ the line limits the reach to Typical application is within aggregation allows to offer some few 100 meters the central office or MDF n times the bandwidth of a based VDSL seems to reach the SDSL service physical limits of typical Broadband workhorse for SDSL performs better than telco copper cables residential and partially the E1/T1 lines in terms of business customers Street cabinet or in-MDU cross-talk placement mandatory to realize high bandwidth Pag e 5
VDSL and VDSL2 – Technical View VDSL touches from today's point of view the technical capabilities of the copper pairs. To be significantly superior to ADSL2+ the cable must not be longer than 1 km. ADSL Technical View Remarks Mbps Datarates vs. cable length 100 VDSL1 is standardized by the ITU as G.993.1, ADSL VDSL2, standardized in 2006 by the ITU as 90 ADSL2+ G.993.2, 80 VDSL2 In practice, only VDSL2 was adopted by the vendors, practically all VDSL deployments are 70 based on VDSL2 WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT Theoretically, VDSL2 can use the transmission 60 of asymmetric and symmetric aggregate data rates above 100 Mbit/s downstream and 50 upstream using a flexible bandwidth of up to 30 40 MHz. VDSL2 is superior to ADSL2+ only in the short 25 30 ranges i.e. < 1km; Starting from 1.6 km the 20 Length (m) performance is similar to ADSL2+. 20 12 8 In order to take full advantage of the high 7 10 bandwidth the deployment of DLSAMs in street cabinets or buildings is required. 0 Countrywide deployments require a large 0 500 1000 1500 2000 2500 3000 amount of active components in the field. A cost efficient operation of VDSL2 is a challenge for the operators Pag e 6
Technology Evaluation xDSL ADSL2 – KPI Evaluation The ADSL/2+ throughput meets the basic broadband requirements, but not the ones of future broadband services (e.g. HD multimedia and IPTV), especially for longer reach. KPI Evaluation – ADSL technologies Main Features Throughput Uplink throughput ADSL offers up to 8 Mbps DL and 10 1Mbps UL, ADSL2+ may be TOPIC-PRESENTATION_RURALBROADBAND_V030_20101222.PPT squeezed up to 24 Mbps DL and 3Mbps UL WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT BB Services Downlink throughput Reach Support Limited to few kilometres (~5 km) 5 QoS support Difficult on the link layer, IP TOS must be mapped on aggregation layer Market Status Reach NGN Capabilities 0 Real NGN apps like RACS are not in the market, doubts if this will be implemented Future Potential Upgrade to VDSL possible Market status Future potential QoS support Mature technology, well understood BB service support Limited support of multimedia NGN Capabilities services, IPTV not possible Pag e 7
Technology Evaluation xDSL VDSL and VDSL2 – KPI Evaluation The VDSL is theoretically able to provide future broadband services at high throughput but only within short ranges, which makes it difficult to implement. KPI Evaluation – VDSL technologies Main Features Throughput Uplink throughput VDSL achieves datarates above 100 10 Mbps (DL / UL) via copper! Reach BB Services But only over very short distance (< Downlink throughput Support 1km) Technical QoS 5 Difficult on the link layer, IP TOS must be mapped on aggregation WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT layer TOPIC-PRESENTATION_RURALBROADBAND_V030_20101222.PPT NGN Capabilities Market Status Reach 0 Real NGN apps like RACS are not in the market, their implementation is expected Future Potential Low, VDSL is close to the physical limits of the copper cables Market status Future potential QoS support Mature technology, well understood BB service support Support of multimedia services and NGN Capabilities IPTV, with restrictions due to the limited reach of 1 km Pag e 8
GPON flavours The infrastructure of xDSL and FTTH makes the stepwise implementation of GPON possible, allowing for a higher flexibility and cost efficiency based on location specifics . Central Office Street Acces End users Cabinet s Unit Copper ADSL WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT Fibre Copper FTTC Fibre Fibre Copper FTTB Fibre FTTH Copper Fibre Pag e 9
Up/ Downstream Transmission One single optical fiber is used to transmit upstream and downstream wavelengths at bit rates of 2.4 Gbps, respectively 1.25 Gbps Transmission Mechanism Downstream: ◦ Upstream: Data is transmitted downstream on 1490nm wavelength at a bit rate of each ONT transmits on wavelength 2.4Gbps 1310nm at bit rate 1.25Gbps The bandwidth per subscriber is dependent on the used splitter ratio Data packets are transmitted in a TDMA Each user uses a specific timeslot manner (time division multiple access) allocated to him to receive its data (Time Division Multiplexing) ONU WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT Optical Power Central Office splitter ONT OLT ONT ONT Upstream Downstream wavelength wavelength range: range: ONT 1260-1360nm 1480-1500nm Source: ITU.T G.984.2 Pag e 10
Optical Splitters Splitters cause optical loss and have a direct influence on the bandwidth delivered to the subscriber. The lower the split ratio the higher is the bandwidth at the subscriber. Optical loss Bandwidth per Optical loss Bandwidth per Subscriber: Subscriber: [dB]: [dB]: 1 : 2 1 : 16 13,5 3,7 1,244 Gbps 155 Mbps 2 : 16 14,3 1 : 4 17,0 78 Mbps 7,0 1 : 32 622 Mbps 2 : 4 7,3 2 : 32 17,5 WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT 1 : 8 10,4 20,5 1 : 64 39 Mbps 311 Mbps 10,7 21,1 2 : 8 2 : 64 1 : 12 19,4 Mbps 12,4 208 Mbps 1 : 128 24,7 Source: ITU.T G.984.x Pag e 11
Optical Distribution Network The ODN consist of three main sections: Feeder, Distribution and Drop, each one of them has a specific range. Two splitters between the OLT and ONT ONT ONT ONT The OLT just see the result: 1:12 split Various combinations of splitter can be used in the GPON design ONT 1:6 It is called decentralized split or cascaded configuration ONT Secon Central Office 1:2 WP3 WORKING SLIDES V08 20110414T0955+02 SLIDES 134-135.PPT d ONT splitte r OLT First Fibre Access Point splitte r Feeder 5-10km Distribute 1- 3 km ONT ONT ONT ONT ONT ONT Drop 100 - 500m Source: ITU.T G.984.x Pag e 12
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