Timing and frequency acquisition for wireless networks

Abstract

Systems and methods are provided for processing Time Domain Multiplexing Pilot symbols by employing complex accumulators to determine peak values which indicate the start of timing and frequency information. In an embodiment, a method is provided for timing acquisition in a wireless network. The method includes acquiring samples from an Orthogonal Frequency Division Multiplexing (OFDM) data packet over a predetermined period of time, where the samples include one or more TDM pilot symbols. The samples are then processed to determine a maximum value that indicates the TDM pilot symbol has been detected.

1 - 14 . (canceled) 
     
     
         15 . A timing module for a wireless network, comprising:
 a time division correlator that processes a superframe field to determine a delayed correlator output;   a correlation function to be processed with the delayed correlator output; and   a filter that determines a peak magnitude value for a pilot sequence from the delayed correlator output.   
     
     
         16 . The module of  claim 15 , further comprising an edge template that matches a front portion of an ideal autocorrelation function for a TDM Pilot 1 symbol. 
     
     
         17 . The module of  claim 16 , a delayed correlator component generates the auto correlation function. 
     
     
         18 . The module of  claim 17 , further comprising an accumulator to buffer samples from the delayed correlator component. 
     
     
         19 . The module of  claim 18 , further comprising a component to analyze the accumulator and determine a peak magnitude value. 
     
     
         20 . The module of  claim 19 , further comprising a detector to determine timing information from the accumulator. 
     
     
         21 . The module of  claim 19 , further comprising a frequency offset estimator to determine a frequency offset for a wireless receiver. 
     
     
         22 . A component for determining timing data in a wireless network, comprising:
 means for analyzing a superframe to determine a delayed output signal;   means for generating a correlation function; and   means for filtering the delayed output signal to determine a peak magnitude value that indicates timing or frequency information.   
     
     
         23 . A machine readable medium having machine executable instructions stored thereon, comprising:
 processing an OFDM packet to determine a delayed correlator output signal;   applying a correlation function to the delayed correlator output signal to determine a start time for an OFDM data packet; and   buffering the delayed correlator output signal to determine a magnitude value associated with the start time.   
     
     
         24 . The machine readable medium of  claim 23 , further comprising applying the correlation function and the delayed correlator output signal to a filter. 
     
     
         25 . The machine readable medium of  claim 24 , further comprising determining a frequency estimate from an output of the filter. 
     
     
         26 . The machine readable medium of  claim 25 , further comprising determining a magnitude value from a complex data set. 
     
     
         27 . The machine readable medium of  claim 26 , the complex data set is derived from a super frame. 
     
     
         28 . The machine readable medium of  claim 26 , further comprising processing the complex data set over a predetermined time frame. 
     
     
         29 . A machine readable medium having a data structure stored thereon, comprising:
 a data field storing delayed correlater values from an OFDM broadcast packet;   a data field to store a correlated function for the OFDM broadcast packet; and   a filter field to determine a start sequence for the OFDM broadcast packet based on determining a magnitude component from the delayed correlator.   
     
     
         30 . A wireless communications apparatus, comprising:
 a memory that includes a component to determine a delayed time division correlator values from a received OFDM broadcast;   a processor that determines a start time for the OFDM broadcast by comparing the delayed time division correlator values to a correlated function; and   a matched filter to accumulate magnitude data that represents timing and frequency information.   
     
     
         31 . A processor that executes instructions for determining timing information for a wireless communication environment, the instructions comprising:
 receiving an OFDM broadcast packet;   determining delayed time domain correlations for the OFDM broadcast packet; and   determining a start time synchronization for a wireless receiver based in part on accumulating magnitude values derived from a received super frame.