and 96 are viewed in window 98 to determine the energy level of that group of impulse responses 90 96 based on that energy level a first local threshold level 100 is set the noise level is shown at 102 anything above threshold 100 is then selected as the identified channel path delays and the delays m 0 m 1 m 2 m 3 can be determined in a second group 104 106 108 110 viewed through a second window 112 a lower energy is detected resulting in a second lower local threshold 114 being set average channel estimator 44 fig6 begins by extracting the ofdm symbol 120 and then performing fft on it 122 the results are normalized by known carriers step 124 in the same way as previously where the known carrier a o accompanied by the frequency response h 0 is normalized by being divided by a 0 to obtain the frequency response h o the average path gains such as 90 96 shown in fig5 b are then estimated 126 using the least squares ls model and the known noise carrier data estimator circuit 50 fig7 may be implemented by performing an fft 130 on a received ofdm signal then building a vector size n with zeros 132 and average path gains 134 inserted in the proper delay locations this is shown in greater detail in fig7 a where the average path gains are shown at 138 and the unknown carriers which receive the zero.