Dec 12, 2014Confidential | Sckipio 1

VDSL vs. G.FAST Technology comparison

Parameter VDSL G.FAST

Frequency Range Up to 30MHz (30a) 2-106MHz, 2-212MHz (future)

Max Rate Up to 250Mbps (30a) and 150Mbps (17a) for short loops, real-world is 30-80Mbps

1Gbps over short loops, exceeding 500 Mbps over real 100m lines

Modulation OFDM OFDM

Number of carriers 4K 2K (for 106MHz profile)

Multiplexing scheme FDD TDD, synchronized among the different copper pairs

Symbol time ~250 μsec (17MHz profile) ~20 μsec

Vectoring Via G.993.5 Supported, with adaptations needed for higher frequency

Tx power Varies by profile, 14.5dBm 4dBm

FEC RS + Trellis code RS + Trellis code

Dec 12, 2014Confidential | Sckipio 2

VDSL vs. G.FAST System comparison

Parameter VDSL G.FAST

Downstream/Upstream ratio Fixed Configurable: 90:10 to 30:70

Customer self-install Questionable. i.e. rates become marginally low

Yes

xDSL Spectral compatibility Issues with 17M/30M mixIssues with CAB/DP Mix

Yes, fresh start with new frequency band

Retrain time Very long (30-90 second range) Very short – few seconds

Rate adaptation Very slow, 128 carriers at a time, SOS not robust

Very fast, quick and robust adaptation – within few msec

Low power mechanisms Under definition, expected savings up to 50%, very slow wake up time

Specified from day one, discontinuous operation, scales with traffic rate