Broadcast digital subscriber lines using discrete multitone for broadband access

摘要

Broadcast digital subscriber lines (BDSL) can provide a cost-effective architecture to deploy digital broadcast services in the near future by utilizing the in-place unshielded twisted-pairs. In the BDSL system, all broadcasting channels can share the same transmitter to reduce the cost. Because all twisted-pairs transmit the same BDSL signal in the downstream direction, both near- and far-end crosstalk can be eliminated. While HDSL and Asymmetrical Digital Subscriber Lines (ADSL) signals are carried at low frequency band, BDSL signals can be transmitted at higher frequency band. A discrete multitone based modulation method is used to increase the efficiency of BDSL. Compared to scheme employing identical modulation for all subchannels, the channel though-put of low frequency subchannels can be increased because of their smaller channel losses and the high frequency subchannels can be utilized even if their signal-to-noise ratios are small. The combination of HDSL, ADSL, and BDSL can provide subscribers many digital one-to-one and broadcasting broadband services.