A transmission schemecontemplates encoding andmodulating digital data ontoa discrete multi-tone signalhaving a total banwidth of atleast 1.6 MHz. The modulationsystem dynamically updatesthe subcarriers used and theamount of data transmittedon each subcarrier duringtransmission (215, 217,219). In one embodiment,the multi-tone encoding andmodulation complies withthe ATIS North AmericanAsymmetric Digital SubscriberLines standard. However,additional subchannels (a totalof 512) and/or subchannelbandwidths of greater than4.3125 kHz may be used. Inthis system, the subchannelsoccurring above frequenciesset forth in the standard aretreated similarly to thosewithin the standard range interms of subcarrier selectioncriteria. This system permitstransmission of digital dataat transmission rates of 6-55Mbps over twisted pair lines at distances of 1200 meters on lines experiencing significant crosstalk noise such as T1 or E1 (215, 217,219) as well as at transmission rates of 10-50+Mbps over distances of 2000 meters.
展开▼
