Ofdm and ofdma profile assignments for cable modems

Abstract

Systems and methods for dynamically updating bit loading profile assignments among a plurality of cable modems.

1 . A system comprising a head end in operable communication with a population of cable modems, each of said cable modems using a respective initial subset of bit loading profiles assigned by the head end, each respective initial subset selected from among a set of initial bit loading profiles used by the head end to communicate to the population of cable modems, the head end dynamically updating at least one respective initial subset to an updated subset based on information determined through the use of the set of initial bit loading profiles in the system. 
     
     
         2 . The system of  claim 1  where the initial subset of bit loading profiles and the updated subset are each determined by the head end based on organizing the population of cable modems into a plurality of groups. 
     
     
         3 . The system of  claim 2  where the head end organizes the population of cable modems into a plurality of groups using a K-means clustering technique. 
     
     
         4 . The system of  claim 3  where information from the initial set of bit loading profiles is used to select seed vectors. 
     
     
         5 . The system of  claim 4  where the initial set of bit loading profiles are used as seed vectors in the K-means clustering technique. 
     
     
         6 . The system of  claim 5  where seed vectors of the K-means clustering technique are selected based on the initial bit loading profiles used by cable modems chosen by the head end from among the population of cable modems. 
     
     
         7 . The system of  claim 6  where the chosen cable modems are selected based on the amount of activity in the cable modems in the system. 
     
     
         8 . The system of  claim 6  where the seed vectors are chosen using a minimum vector distance between the seed vectors. 
     
     
         9 . The system of  claim 4  where using information from the initial set of bit loading profiles to determine the seed vectors reduces perturbation of the system relative to randomly selecting seed vectors. 
     
     
         10 . The system of  claim 1  where the information determined through the use of the set of initial bit loading profiles in the system comprises a plurality of optimum bit loading vectors associated with the most used cable modems in the system. 
     
     
         11 . A method for updating bit loading profiles among a plurality of cable modems each communicating with a head end, the method comprising:
 assigning respective first subsets of bit loading profiles to each of the plurality of cable modems, each of the respective first subsets selected from a larger set of bit loading profiles used by the head end; and   using information from the larger set of bit loading profiles to update at least one respective first subset of bit loading profiles.   
     
     
         12 . The system of  claim 11  where first subsets of bit loading profiles and the updated at least one respective first subset are each determined based on organizing the population of cable modems into a plurality of groups. 
     
     
         13 . The system of  claim 12  including organizing the population of cable modems into a plurality of groups using a K-means clustering technique. 
     
     
         14 . The system of  claim 13  including using information from the initial set of bit loading profiles to select seed vectors. 
     
     
         15 . The system of  claim 14  including using the initial set of bit loading profiles as seed vectors in the K-means clustering technique. 
     
     
         16 . The system of  claim 15  where seed vectors of the K-means clustering technique are selected based on the initial bit loading profiles used by cable modems chosen by the head end from among the population of cable modems. 
     
     
         17 . The system of  claim 16  selecting the chosen cable modems based on the amount of activity in the cable modems in the system. 
     
     
         18 . The system of  claim 16  including choosing the seed vectors using a minimum vector distance between the seed vectors. 
     
     
         19 . The system of  claim 14  where using information from the initial set of bit loading profiles to determine the seed vectors reduces perturbation of the system relative to randomly selecting seed vectors. 
     
     
         20 . The system of  claim 11  including dynamically updating the set of initial bit loading profiles to an updated set of bit loading profiles using information from the set of initial bit loading profiles.