Abstract: The present invention relates to a method for estimating a bit error probability using an error rate ratio of a frame synchronization word, to lower computational complexity such that the method can be implemented in a relatively simple and economical way at a high computational speed. The method includes the steps of: a) defining error rate ratios of frame synchronization words; b) setting a weighted least squares cost function with weights greater than or equal to 0 for the bit error probability using the error rate ratios of the frame synchronization words set in the step a); c) obtaining an estimated bit error probability value that minimizes the cost function set in the step b); and d) sequentially obtaining the weights so that a mean squared error of the estimated bit error probability value obtained in the step c) becomes small.