Patent ID: 7953190

Claim:
A mobile station having a parallel sliding window correlator apparatus for preamble searching in a wireless network, comprising: a delay line device for receiving an input signal representative of a received signal from the wireless network, the delay line device providing a plurality of outputs including a first output r(n), a second output r(n−D), a third output r(n−2D), a first filtered output r 2 (m), a second filtered output r 2 (m−D/2) and a third filtered output r 2 (m−D); a first FFT section coupled to the delay line device and receiving the first output, the second output and the third output, the first FFT section including a plurality of nodes for processing the first, second and third outputs, a first one of the plurality of nodes of the first FFT section for obtaining a first correlation magnitude signal, a second one of the plurality of nodes for obtaining a first energy level signal corresponding to a first energy level of the received signal, a third one of the plurality of nodes for scaling the first energy level signal by a predetermined first threshold to obtain a first scaled signal, and a fourth one of the plurality of nodes for taking the difference between the first correlation magnitude signal and the first scaled signal to generate a first delay correlation detection indication signal; and a second FFT section coupled to the delay line device and receiving the first filtered output, the second filtered output and the third filtered output, the second FFT section including a plurality of nodes for processing the first, second and third filtered outputs, a first one of the plurality of nodes of the second FFT section for obtaining a second correlation magnitude signal, a second one of the plurality of nodes for obtaining a second energy level signal corresponding to a second energy level of the received signal, a third one of the plurality of nodes for scaling the second energy level signal by a predetermined second threshold to obtain a scaled signal, and a fourth one of the plurality of nodes for taking the difference between the second correlation magnitude signal and the second scaled signal to generate a second delay correlation detection indication signal; wherein the first FFT section is an N-size FFT section and the second FFT section is an N/2 size FFT section, the N-size FFT section searches for a first preamble associated with a first channel bandwidth and the N/2 size FFT section searches for a second preamble associated with a second channel bandwidth, and processing to obtain the first and second delay correlation detection indication signals is performed in parallel.