Methods and Apparatus for Preamble Detection in A Communication Network

Abstract

Methods and apparatus for preamble detection in a communication network are disclosed. In an exemplary embodiment, a method includes retrieving parameters from a parameter database, filling a buffer of preamble data received in an uplink transmission from user equipment, and frequency shifting the buffer of preamble data based on one or more first parameters to generate frequency shifted data. The method also includes oversampling the frequency shifted data to generates oversampled data, downsampling the over sampled data based on one or more second parameters to generate preamble samples, and updating the parameter database with updated values for the one or more first and second parameters. The method also includes repeating all the operations until a selected amount of preamble samples is obtained.

What is claimed is: 
     
         1 . A method for identifying preamble information in a communication network, comprising:
 receiving input data containing uplink data samples from user equipment via a communication network;   generating downsampled data in accordance with the input data via a detector utilizing parameters stored in a parameter database;   generating a correlated output via operation of correlating selected amount of downsampled data in response to a signature sequence; and   detecting a preamble in accordance with the correlated output through a performance of peak detection.   
     
     
         2 . The method of  claim 1 , further comprising obtaining the signature sequence from a signature sequence generator. 
     
     
         3 . The method of  claim 1 , further comprising retrieving one or more parameters from the parameter database to a frequency shifter. 
     
     
         4 . The method of  claim 1 , further comprising storing at least a portion of an uplink transmission in a buffer of preamble data for sampling. 
     
     
         5 . The method of  claim 1 , further comprising generating frequency shifted data via operation of frequency shifting of buffered preamble data based on one or more parameters. 
     
     
         6 . The method of  claim 1 , further comprising generating oversampled data through operation of oversampling frequency shifted data. 
     
     
         7 . The method of  claim 1 , further comprising generating preamble samples via operation of downsampling oversampled data based on one or more parameters. 
     
     
         8 . The method of  claim 1 , further comprising updating values of one or more parameters in response to sampling process and storing updated parameters in the parameter database. 
     
     
         9 . The method of  claim 1 , further comprising repeating sampling operations until a selected amount of preamble samples is obtained. 
     
     
         10 . The method of  claim 1 , further comprising identifying the signature sequence via a matrix of preamble formats. 
     
     
         11 . The method of  claim 1 , further comprising identifying an accumulated phase value for frequency shifting from the parameters. 
     
     
         12 . The method of  claim 1 , further comprising identifying filter states represented by accumulator values for all stages in a cascaded integrator comb (“CIC”) downsampler from one or more parameters. 
     
     
         13 . The method of  claim 1 , further comprising performing sample copying for an operation of oversampling. 
     
     
         14 . The method of  claim 1 , further comprising performing downsampling via a process of oversampled data with a cascaded integrator comb (“CIC”) downsampler. 
     
     
         15 . A method for detecting preambles in a communication network, comprising:
 retrieving one or more parameters from a parameter database and storing the parameters in an accumulated phase value storage in a frequency shifter;   receiving a frequency shift input indicating an amount of frequency shift to be applied;   generating an input via adding the frequency shift input and the parameters; and   generating a frequency shifted data in response to the input and an input data retrieved from a buffer.   
     
     
         16 . The method of  claim 15 , further comprising determining a phase value based on the input by a phase computation circuit. 
     
     
         17 . The method of  claim 16 , further comprising generating a complex sinusoid value based on the phase value via a phase conversion circuit. 
     
     
         18 . The method of  claim 15 , wherein generating a frequency shifted data includes multiplying the input data with a complex sinusoid value generated by a phase conversion circuit. 
     
     
         19 . The method of  claim 15 , further comprising generating oversampled data through operation of oversampling frequency shifted data. 
     
     
         20 . The method of  claim 15 , further comprising generating preamble samples via operation of downsampling oversampled data based on the parameters. 
     
     
         21 . The method of  claim 15 , further comprising updating values of one or more parameters in response to sampling process and storing updated parameters in the parameter database. 
     
     
         22 . The method of  claim 15 , further comprising repeating sampling operations until a selected amount of preamble samples is obtained. 
     
     
         23 . The method of  claim 15 , further comprising correlating selected amount of preamble samples with a signature sequence to generate a correlated output. 
     
     
         24 . The method of  claim 23 , further comprising performing peak detection on the correlated output to detect a transmitted preamble. 
     
     
         25 . The method of  claim 23 , further comprising identifying the signature sequence via a matrix of preamble formats. 
     
     
         26 . An apparatus for identifying preamble information in a communication network, comprising:
 means for receiving input data containing uplink data samples from user equipment via a communication network;   means for generating downsampled data in accordance with the input data via a detector utilizing parameters stored in a parameter database;   means for generating a correlated output via operation of correlating selected amount of downsampled data in response to a signature sequence; and   means for detecting a preamble in accordance with the correlated output through a performance of peak detection.   
     
     
         27 . The apparatus of  claim 26 , further comprising means for obtaining the signature sequence from a signature sequence generator. 
     
     
         28 . The apparatus of  claim 26 , further comprising means for retrieving one or more parameters from the parameter database to a frequency shifter. 
     
     
         29 . The apparatus of  claim 26 , further comprising means for storing at least a portion of an uplink transmission in a buffer of preamble data for sampling. 
     
     
         30 . An apparatus for detecting preambles in a communication network, comprising:
 means for retrieving one or more parameters from a parameter database and means for storing the parameters in an accumulated phase value storage in a frequency shifter;   means for receiving a frequency shift input indicating an amount of frequency shift to be applied;   means for generating an input via adding the frequency shift input and the parameters; and   means for generating a frequency shifted data in response to the input and an input data retrieved from a buffer.   
     
     
         31 . The apparatus of  claim 30 , further comprising means for determining a phase value based on the input by a phase computation circuit. 
     
     
         32 . The apparatus of  claim 30 , further comprising means generating a complex sinusoid value based on the phase value via a phase conversion circuit. 
     
     
         33 . The apparatus of  claim 30 , wherein means for generating a frequency shifted data includes means for multiplying the input data with a complex sinusoid value generated by a phase conversion circuit. 
     
     
         34 . The apparatus of  claim 30 , further comprising means generating oversampled data through operation of oversampling frequency shifted data. 
     
     
         35 . The apparatus of  claim 30 , further comprising means generating preamble samples via operation of downsampling oversampled data based on the parameters.