Combined OFDMA preamble index identification, integer frequency offset estimation, and preamble CINR measurement

A process for the evaluation of candidate preambles for best Carrier to Interference plus Noise Ratio (CINR), each candidate preamble accompanied by an integer frequency offset and a preamble index, the process operative on a signal processor and having the steps:

• forming a first value by summing the power in the subcarriers of said candidate preamble;
• dropping the edge subcarriers of said candidate preamble and applying said candidate preamble subcarriers without said edge subcarriers to the input of an adder, forming subcarrier coefficients Wk from the frequency domain transform of a time domain step function, forming a smoothed value by convolving said coefficients Wk with said candidate preamble subcarriers and dropping the edge subcarriers thereof, negating said smoothed value and applying said negated smoothed value to said adder, thereafter computing the power of each subcarrier of said adder output and summing said adder output subcarriers power to form a second value;
• computing a signal and interference value from said first value, said second value, and a noise value;
• computing a Carrier to Interference plus Noise Ratio (CINR) value from said signal value and said interference value and associating said CINR value with said integer frequency offset and said preamble index associated with said candidate preamble;
• replacing said CINR value and said associated integer frequency offset and said preamble index in a table containing an entry with a lower CINR value.