Delivering Wireless/Wireline Transparency

We have said that one of the objectives in 3G network design is to deliver wireless/
wireline transparency. The problem is that to deliver performance equivalence, we
would need to match wireline throughput, wireline quality, and wireline consistency.
Our expectation of the bit rate/throughput is determined by whether we use ISDN
(144 kbps) or ATM (2.048 Mbps, 51, 155, or 622 Mbps, or 2.5 Gbps) or ADSL (8 Mbps
down, 640 kbps up) or VDSL (40 Mbps over 2048 frequency bands). ADSL and VDSL
are essentially mechanisms for releasing useful bandwidth in the copper access network
(last-mile drop). ADSL and G.Lite (splitterless ADSL) occupies copper bandwidth
between 20 kHz and 1104 kHz. The G.Lite specification is 1.5 Mbps downstream
and 512 kbps upstream, giving an 1800-ft reach over twisted pair at 1 in 1010 bit error
rate (a distance/quality metric).
Similar throughput gains are being achieved in hybrid fiber/co-ax networks. As
with twisted pair, the objective is to user higher frequencies in the co-ax to deliver more
bandwidth—potentially up to 900 MHz. Bandwidth provision is predominantly
downlink-biased, optimized to deliver content to subscribers rather than capture content
from subscribers. As we said earlier, this may not be appropriate, given that uplink
loading may tend to increase over time.