SIGNALING TO APPLICATION LACK OF REQUESTED BANDWIDTH

1 . A method performed on a computing device, the method comprising:

receiving, by the computing device, a serial digital data stream;

converting, by the computing device, the received serial digital data stream into a plurality of parallel digital data streams;

modulating, by the computing device, each of the plurality of parallel digital data streams onto a separate subchannel, where each separate subchannel is one of a plurality of subchannels of a channel, where the separate subchannels are selected based on a requested data transmission rate and on noise levels detected on various of the plurality of subchannels, the modulating resulting in modulated parallel digital data streams;

converting, by the computing device, the modulated parallel digital data streams into a modulated serial digital data stream;

converting, by the computing device, the modulated serial digital data stream into a modulated analog data stream that represents the received serial digital data stream; and

transmitting, by the computing device, the modulated analog data stream.

2 . The method of claim 1 where each of the plurality of parallel digital data streams comprises frames of data divided from the received serial digital data stream.

3 . The method of claim 1 where the modulating is based at least in part on a phase shift keying modulation scheme.

4 . The method of claim 1 where the modulating is based at least in part on a quadrature amplitude modulation scheme.

5 . The method of claim 1 further comprising selecting, based on a required data rate, a modulation scheme used in the modulating.

6 . The method of claim 1 further comprising selecting, based on available subchannels, a modulation scheme used in the modulating.

7 . The method of claim 1 further comprising adding, prior to the convertings, a cyclic prefix to each of the modulated parallel digital data streams.

8 . A system comprising a computing device and at least one program module that are together configured for performing actions comprising:

receiving, by the computing device, a serial digital data stream;

converting, by the computing device, the received serial digital data stream into a plurality of parallel digital data streams;

modulating, by the computing device, each of the plurality of parallel digital data streams onto a separate subchannel, where each separate subchannel is one of a plurality of subchannels of a channel, where the separate subchannels are selected based on a requested data transmission rate and on noise levels detected on various of the plurality of subchannels, the modulating resulting in modulated parallel digital data streams;

converting, by the computing device, the modulated parallel digital data streams into a modulated serial digital data stream;

converting, by the computing device, the modulated serial digital data stream into a modulated analog data stream that represents the received serial digital data stream; and

transmitting, by the computing device, the modulated analog data stream.

9 . The system of claim 8 where each of the plurality of parallel digital data streams comprises frames of data divided from the received serial digital data stream.

10 . The system of claim 8 where the modulating is based at least in part on a phase shift keying modulation scheme.

11 . The system of claim 8 where the modulating is based at least in part on a quadrature amplitude modulation scheme.

12 . The system of claim 8 further comprising selecting, based on a required data rate, a modulation scheme used in the modulating.

13 . The system of claim 8 further comprising selecting, based on available subchannels, a modulation used in the modulating.

14 . The system of claim 8 further comprising adding, prior to the convertings, a cyclic prefix to each of the modulated parallel digital data streams.

15 . At least one computer storage device having stored thereon computer-readable instructions that, when executed by a computing device, cause the computing device to perform actions comprising:

receiving, by the computing device, a serial digital data stream;

converting, by the computing device, the received serial digital data stream into a plurality of parallel digital data streams;

modulating, by the computing device, each of the plurality of parallel digital data streams onto a separate subchannel, where each separate subchannel is one of a plurality of subchannels of a channel, where the separate subchannels are selected based on a requested data transmission rate and on noise levels detected on various of the plurality of subchannels, the modulating resulting in modulated parallel digital data streams;

converting, by the computing device, the modulated parallel digital data streams into a modulated serial digital data stream;

converting, by the computing device, the modulated serial digital data stream into a modulated analog data stream that represents the received serial digital data stream; and

transmitting, by the computing device, the modulated analog data stream.

16 . The at least one computer storage device of claim 15 where each of the plurality of parallel digital data streams comprises frames of data divided from the received serial digital data stream.

17 . The at least one computer storage device of claim 15 here the modulating is based at least in part on a phase shift keying modulation scheme or on a quadrature amplitude modulation scheme.

18 . The at least one computer storage device of claim 15 further comprising selecting, based on a required data rate, a modulation scheme used in the modulating.

19 . The at least one computer storage device of claim 15 further comprising selecting, based on available subchannels, a modulation scheme used in the modulating.

20 . The at least one computer storage device of claim 15 further comprising adding, prior to the convertings, a cyclic prefix to each of the modulated parallel digital data streams.