Downstream adaptive modulation in broadband communications systems

Abstract

A downstream adaptive modulation system and method. The downstream adaptive modulation system comprises a wireless access termination system and one or more wireless modems. The wireless access termination system includes a plurality of queues and a parser. The parser parses data traffic onto the plurality of queues. Each queue is associated with a different coding and modulation scheme. Each of the one or more wireless modems receives data traffic from the plurality of queues based on the wireless modem's ability to demodulate and decode the signal from each of the plurality of queues. When a wireless modem experiences a change in signal strength, the present invention enables the wireless modem to adapt to data from other queues to compensate for the change in signal strength. Thus, if the signal strength improves over a period of time, the wireless modem may receive data at a higher order modulation and FEC code rate. If the signal strength weakens over a period of time, the wireless modem may receive data at a lower order modulation and FEC code rate.

What is claimed is: 
     
         1 . An adaptive modulation receiver, comprising:
 a splitter configured to split a data stream signal into a plurality of data streams;   a plurality of demodulators, each demodulator from among the plurality of demodulators being configured to demodulate data from a respective data stream from among the plurality of data streams in accordance with a respective demodulation scheme from among a plurality of demodulation schemes; and   a plurality of queues, each queue from among the plurality of queues being associated with a respective demodulator from among the plurality of demodulators.   
     
     
         2 . The adaptive modulation receiver of  claim 1 , further comprising:
 a transceiver, coupled to the splitter, configured to receive the data stream over a communications channel.   
     
     
         3 . The adaptive modulation receiver of  claim 1 , wherein each demodulator from among the plurality of demodulators is associated with a demodulation scheme having a different order. 
     
     
         4 . The adaptive modulation receiver of  claim 1 , further comprising:
 a multiplexer configured to select data from each queue from among the plurality of queues.   
     
     
         5 . The adaptive modulation receiver of  claim 4 , further comprising:
 a plurality of decoders, each decoder from among the plurality of decoders being configured to decode data from a respective data stream from among the plurality of data streams in accordance with a respective decoding scheme from among a plurality of decoding schemes.   
     
     
         6 . The adaptive modulation receiver of  claim 4 , further comprising:
 a media access controller (MAC), coupled to the multiplexer, configured to extract data output from the multiplexer.   
     
     
         7 . The adaptive modulation receiver of  claim 1 , further comprising:
 a plurality of filters, coupled to the splitter and to the plurality of demodulators, configured to couple each data stream from among the plurality of data streams to its respective demodulator based on a corresponding data stream frequency band.   
     
     
         8 . The adaptive modulation receiver of  claim 4 , wherein the data from each queue from among the plurality of queues is selected by the multiplexer to provide a Moving Picture Experts Group (MPEG) data stream. 
     
     
         9 . An adaptive modulation receiver, comprising:
 a plurality of demodulators, each demodulator from among the plurality of demodulators being configured to demodulate a respective signal from among a plurality of signals in accordance with a demodulation scheme that is associated with its respective signal;   a plurality of queues, each queue from among the plurality of queues being configured to store demodulated data associated with its respective demodulator from among the plurality of demodulators; and   a multiplexer configured to combine demodulated data from each queue from among the plurality of queues into a data stream.   
     
     
         10 . The adaptive modulation receiver of  claim 9 , further comprising:
 a splitter configured to separate a composite signal received over a communications channel into the plurality of signals.   
     
     
         11 . The adaptive modulation receiver of  claim 9 , wherein each demodulator from among the plurality of demodulators is associated with a demodulation scheme having a different order. 
     
     
         12 . The adaptive modulation receiver of  claim 9 , wherein the data stream is a Moving Picture Experts Group (MPEG) data stream, and further comprising:
 a media access controller (MAC), coupled to the multiplexer, configured to extract data from the MPEG data stream.   
     
     
         13 . The adaptive modulation receiver of  claim 9 , further comprising:
 a plurality of filters, coupled to the splitter and to the plurality of demodulators, configured to couple each signal from among the plurality of signals to its respective demodulator.   
     
     
         14 . The adaptive modulation receiver of  claim 9 , wherein each demodulator from among the plurality of demodulators is further associated with a decoding scheme from among a plurality of decoding schemes, and further comprising:
 a plurality of decoders, each decoder from among the plurality of decoders being configured to decode the signal coupled to its respective demodulator in accordance with a decoding scheme that is associated with its respective signal.   
     
     
         15 . In an adaptive modulation receiver, a method comprising:
 splitting a composite signal received over a communications channel into a plurality of signals;   demodulating the plurality of signals according to a demodulation scheme associated with a respective signal from among the plurality of signals to provide demodulated data corresponding to each of the plurality of signals;   separately queuing the demodulated data corresponding to each of the plurality of signals to provide a plurality of data queues;   combining the plurality of data queues to provide a data stream; and   sending the data stream to a user device.   
     
     
         16 . The method of  claim 15 , wherein each demodulation scheme associated with a respective signal from among the plurality of signals has a different order. 
     
     
         17 . The method of  claim 15 , wherein the combining comprises:
 combining the plurality of data queues to provide a Moving Picture Experts Group (MPEG) data stream.   
     
     
         18 . The method of  claim 17 , further comprising:
 extracting data from the MPEG data stream.   
     
     
         19 . The method of  claim 15 , further comprising:
 filtering the plurality of signals; and   coupling each filtered signal from among the plurality of signals to its respective demodulator from among the plurality of demodulators.   
     
     
         20 . The method of  claim 15 , further comprising:
 decoding the plurality of signals according to a decoding scheme associated with a respective signal from among the plurality of signals.