Multi-mode transmitter for highly-spectrally-efficient communications

Abstract

A transmitter may comprise a symbol mapping circuit that is configurable to operate in at least two configurations, wherein a first of the configurations of the symbol mapping circuit uses a first symbol constellation and a second of the configurations of the symbol mapping circuit uses a second symbol constellation. The transmitter may also comprise a pulse shaping circuit that is configurable to operate in at least two configurations, wherein a first of the configurations of the pulse shaping circuit uses a first set of filter taps and a second of the configurations of the pulse shaping circuit uses a second set of filter taps. The first set of filter taps may correspond to a root raised cosine (RRC) filter and the second set of filter taps corresponds to a partial response filter.

What is claimed is: 
     
       1. A system comprising:
 a transmitter configurable to operate in at least two modes, wherein:
 which of said modes said transmitter is configured into is controlled based on: feedback or request from a receiver, a measured performance indicator, and/or a command from an application running on a device in which said transmitter is installed; 
 while said transmitter is configured into a first of said modes, said transmitter is configured to use a pulse shaping filter configured as a near zero positive ISI filter; 
 while said transmitter is configured into a second of said modes, said transmitter is configured to generate an inter-symbol correlated (ISC) signal; 
 a symbol constellation used by said transmitter while said transmitter is configured into said first of said modes is the same as a symbol constellation used while said transmitter is configured into said second of said modes; 
 said transmitter comprises an amplifier; 
 while said transmitter is configured into said first of said modes, a first amount of power back-off is used by said amplifier; and 
 while said transmitter is configured into said second of said modes, a second amount of power back-off is used by said amplifier. 
 
 
     
     
       2. The system of  claim 1 , wherein a maximum throughput achievable while said transmitter is configured into said first of said modes is equal to a maximum throughput achievable while said transmitter is configured into said second of said modes. 
     
     
       3. The system of  claim 1 , wherein said symbol constellation is an N-QAM constellation, N being an integer. 
     
     
       4. The system of  claim 1 , wherein while said transmitter is configured into the second of said modes, said transmitter is configured to process signals to be transmitted via a partial response pulse shaping filter. 
     
     
       5. The system of  claim 1 , wherein a bandwidth used by said transmitter while said transmitter is configured into said first of said modes is greater than a bandwidth used by said transmitter while said transmitter is configured into said second of said modes. 
     
     
       6. A method comprising:
 performing in a transmitter configurable to operate in at least two modes:
 controlling into which of said modes said transmitter is configured based on: feedback or request from a receiver, a measured performance indicator, and/or a command from an application running on a device in which said transmitter is installed; 
 while said transmitter is configured into a first of said modes, mapping bits to symbols using a particular symbol constellation and transmitting said symbols onto a channel using a pulse shaping filter configured as a near zero positive ISI filter; 
 while said transmitter is configured into a second of said modes, mapping bits to symbols using said particular symbol constellation and transmitting said symbols onto said channel using a pulse shaping filter configured to generate an inter-symbol correlated (ISC) signal; 
 while said transmitter is configured into said first of said modes, amplifying an output of said pulse shaping filter configured as a near zero positive ISI filter using a first amount of power back-off; and 
 while said transmitter is configured into said second of said modes, amplifying said ISC signal using a second amount of power back-off. 
 
 
     
     
       7. The system of  claim 6 , wherein a maximum throughput achievable while said transmitter is configured into said first of said modes is equal to a maximum throughput achievable while said transmitter is configured into said second of said modes. 
     
     
       8. The system of  claim 6 , wherein said particular symbol constellation is an N-QAM constellation, N being an integer. 
     
     
       9. The system of  claim 6 , wherein while said transmitter is configured into the second of said modes, said pulse shaping filter is configured as a partial response pulse shaping filter. 
     
     
       10. The system of  claim 6 , wherein a bandwidth used by said transmitter while said transmitter is configured into said first of said modes is greater than a bandwidth used by said transmitter while said transmitter is configured into said second of said modes. 
     
     
       11. A system comprising:
 a transmitter configurable to operate in at least two modes, wherein:
 which of said modes said transmitter is configured into is controlled based on: feedback or request from a receiver; a measured performance indicator, and/or an application running on a device in which said transmitter is installed; 
 while said transmitter is configured into a first of said modes, said transmitter is configured to use a pulse shaping filter configured as a near zero positive ISI filter; 
 while said transmitter is configured into a second of said modes, said transmitter is configured to generate an inter-symbol correlated (ISC) signal; 
 a symbol constellation used by said transmitter while said transmitter is configured into said first of said modes is the same as a symbol constellation used while said transmitter is configured into said second of said modes; and 
 a maximum throughput achievable while said transmitter is configured into said first of said modes is equal to a maximum throughput achievable while said transmitter is configured into said second of said modes. 
 
 
     
     
       12. The system of  claim 11 , wherein said symbol constellation is an N-QAM constellation, N being an integer. 
     
     
       13. The system of  claim 11 , wherein while said transmitter is configured into the second of said modes, said transmitter is configured to process signals to be transmitted via a partial response pulse shaping filter. 
     
     
       14. The system of  claim 11 , wherein a bandwidth used by said transmitter while said transmitter is configured into said first of said modes is greater than a bandwidth used by said transmitter while said transmitter is configured into said second of said modes. 
     
     
       15. A system comprising:
 a transmitter configurable to operate in at least two modes, wherein:
 which of said modes said transmitter is configured into is controlled based on: feedback or request from a receiver; a measured performance indicator, and/or an application running on a device in which said transmitter is installed: 
 while said transmitter is configured into a first of said modes, said transmitter is configured to use a pulse shaping filter configured as a near zero positive ISI filter; 
 while said transmitter is configured into a second of said modes, said transmitter is configured to generate an inter-symbol correlated (ISC) signal; 
 a symbol constellation used by said transmitter while said transmitter is configured into said first of said modes is the same as a symbol constellation used while said transmitter is configured into said second of said modes; and 
 a bandwidth used by said transmitter while said transmitter is configured into said first of said modes is greater than a bandwidth used by said transmitter while said transmitter is configured into said second of said modes. 
 
 
     
     
       16. The system of  claim 15 , wherein said symbol constellation is an N-QAM constellation, N being an integer. 
     
     
       17. The system of  claim 15 , wherein while said transmitter is configured into the second of said modes, said transmitter is configured to process signals to be transmitted via a partial response pulse shaping filter. 
     
     
       18. A method comprising:
 performing in a transmitter configurable to operate in at least two modes:
 controlling into which of said modes said transmitter is configured based on: feedback or request from a receiver, a measured performance indicator, and/or a command from an application running on a device in which said transmitter is installed; 
 while said transmitter is configured into a first of said modes, mapping bits to symbols using a particular symbol constellation and transmitting said symbols onto a channel using a pulse shaping filter configured as a near zero positive ISI filter; 
 while said transmitter is configured into a second of said modes, mapping bits to symbols using said particular symbol constellation and transmitting said symbols onto said channel using a pulse shaping filter configured to generate an inter-symbol correlated (ISC) signal; and 
 wherein a maximum throughput achievable while said transmitter is configured into said first of said modes is equal to a maximum throughput achievable while said transmitter is configured into said second of said modes. 
 
 
     
     
       19. The system of  claim 18 , wherein said particular symbol constellation is an N-QAM constellation, N being an integer. 
     
     
       20. The system of  claim 18 , wherein while said transmitter is configured into the second of said modes, said pulse shaping filter is configured as a partial response pulse shaping filter. 
     
     
       21. The system of  claim 18 , wherein a bandwidth used by said transmitter while said transmitter is configured into said first of said modes is greater than a bandwidth used by said transmitter while said transmitter is configured into said second of said modes. 
     
     
       22. A method comprising:
 performing in a transmitter configurable to operate in at least two modes:
 controlling into which of said modes said transmitter is configured based on: feedback or request from a receiver, a measured performance indicator, and/or a command from an application running on a device in which said transmitter is installed; 
 while said transmitter is configured into a first of said modes, mapping bits to symbols using a particular symbol constellation and transmitting said symbols onto a channel using a pulse shaping filter configured as a near zero positive ISI filter; and 
 while said transmitter is configured into a second of said modes, mapping bits to symbols using said particular symbol constellation and transmitting said symbols onto said channel using a pulse shaping filter configured to generate an inter-symbol correlated (ISC) signal; and 
 wherein a bandwidth used by said transmitter while said transmitter is configured into said first of said modes is greater than a bandwidth used by said transmitter while said transmitter is configured into said second of said modes. 
 
 
     
     
       23. The system of  claim 22 , wherein said particular symbol constellation is an N-QAM constellation, N being an integer.