VDSL Access Networks lectures 2008/09 Ľ. Maceková – KEMT – FEI –TU -KE

30 MHz up to 52 Mbps split Upstream and Downstream Fig.1 – VDSL architecture – max. downstream only to 300 m ([6], variable freq.bands up to 1,5 km Data up Data down

VDSL classService type Downstrea m speed [Mbps] Upstream speed [Mbps] Reach – best- / worst one [m] I (asymmetric) A423,2684, / 453 A314,4643, / 729 A28,5762,048 (E1)1691 / 789 A16,42,048 (E1)1791 / 843 II (symmetrical) S528, / 212 S423, / 261 S314, / 575 S28, / 820 S16, / 876 Tab. 1 Data speeds and reach by ETSI (Europe); for wires Φ 0,4 mm

Fig.2 General reference VDSL model (by ITU-T) [1]

Fig.3 Functional reference model VTU-x by ITU -T [1]

Fig.4 … by ITU [1]

Fig.5 Symmetrical and asymmetrical VDSL services ISDN or POTS VDSL down stream VDSL upstream Asymmetrical traffic Symmetrical traffic VDSL upstream frequency

Fig.6 DMT – VDSL spectrum (in combination with analog telephone) [7] frequency telephone spectrum Fig.7 VDSL downstream (DS) and upstream (US) subbands alocation – generally [1] - see next slide...

Fig.8 The different frequency plans for VDSL by ITU [1] (Opt = Optional (yes/no, DS/US)

Tab. 2 An example of VDSL mask in downstreams DS1,DS2 described in standard ITU-T G.993.1

Fig. 9 VDSL transport modes possibilities [2] STM – synchronous transport mode

Fig.10 DSL network [6,8]

- ITU-T G (2006) - enhanced VDSL version – the goal: do not lose customers in competitive with “cable” VoIP, Internet, digital TV and VoD-HD providers - freq, band up to 30 MHz - symmetric up- and down- streams each of 100 Mbps (aggregate data speed 200 Mbps) - reach to 2,5 km ( US0 band - to 276kHz, EC, TEQs) - several profiles - Zipper DMT (DMT based duplex – subcarrier bands, each 4 or 8kHz wide – from 2048 to 4096 bands – see next fig.) – allocation of subcarriers and data speed adaptation accordingly to immediate requirements of applications on the both sides of line - trellis encoding - STM and PTM supporting - interoperability with ADSL devices, there are also several profiles (8) for different applications – see tab. 3 and fig.12 in the next slides  VDSL2

Fig. 11 VDSL2 spectrum utilization and comparison with ADSL2 and ADSL2+ Tab. 3 VDSL2 profiles

Fig.12 VDSL2 profiles in comparison with ADSL and ADSL2+

Profi le Bandwidt hBandwidt h (MHz)MHz Number of carriers Carrier bandwidth (kHz) Power (dBm)dBm Max. Throughput (Mbit/s, downstream) Throughput 8a8, , ,550 8b8, , ,550 8c8,519724, ,550 8d8, , ,550 12a , ,568 12b , ,568 17a17, , , a ,625+14,5100 Tab. 4 VDSL2 profiles [Wikipedia]

Fig. 1 ones more comparison ADSL and VDSL: data speeds and reach (4500 f = 1,47 km, feet=5,5 km)

other xDSL systems

 FDSL – fiber DSL (but also other relevances) [5] Fig.15 Using fiber to span long distance; hybrid technology (optical / copper lines)

 PDSL [5] - it was described already

Fig.16 Architecture of BDSL technology [4]  BDSL – Broadcast DSL - it is dedicated for distribution of more TV (up to several tens) channels, which share transport medium (twisted pairs) with analog teleph. line (point-to-multipoint technology) Analog. signals are digitized, and together with digital TV channels are compressed. There are used 3 subcarriers – 40 kHz, 80 kHz and 1,2 MHz..., DSLAM; ATM technology Subscriber lines - standard submitted to Committee T1E1.4,

References [1] ITU-T G Recommendation, 2004 [2] W. J. Goralski: ADSL and DSL Technologies. Sec. Edition.Osborne Mc.Graw- Hill, [3] ITU-T G Recommendation, [4] Vaculík: Prístupové siete. ŽU v Žiline, [5] J.Dúha, P. Podhradský, P. Trúchly: Technológie v prístupových sieťach a procesy ich integrácie do NGN. (Projekt: NGN- multimédiá, multimed.ICT technológie,....) Bratislava, [6] L. Harte: Introduction to Digital Subscriber Line (DSL): Technologies, Operation and Systems. ALTHOS, [7] K.Blunár, Z. Diviš: Telekomunikačné siete, časť IV..- skriptum ŽU v Žiline, K.Blunár, Z. Diviš: Telekomunikačné siete, časť IV..- skriptum ŽU v Žiline, 2000 [8] arch.htm# [9] rtBody;col1