Patent ID: 8345804

Claim:
A method of detecting a preamble sequence in a signal in a Universal Mobile Telecommunications System (UMTS) Long Term Evolution (LTE) system, the method comprising: receiving a wideband OFDM signal comprising a burst of a random access channel (RACH); filtering a narrow band signal from the wideband OFDM signal, wherein the narrow band signal comprises the preamble sequence, and wherein the filtering operation filters or extracts RACH information which has been mapped to at least one physical resource block of a spectrum in the LTE system; down sampling the filtered signal by a factor of N; wherein N is an integer greater than 1; applying RADIX-2 FFT processing to convert the down sampled signal from a time domain signal to a frequency domain signal; extracting a narrow band random access channel (RACH) signal from the frequency domain filtered signal; correlating the extracted signal with a reference sequence to generate a frequency domain correlation sequence output; obtaining a time domain correlation sequence output through inverse discrete Fourier transform processing of the frequency domain correlation sequence output; and detecting a peak of the time domain correlation sequence output, wherein the peak of the time domain correlation sequence output is the preamble sequence.