We present a novel BCH code based sequences design method for generating large families of ranging sequences. The sequences can be used in an OFDMA network to offer sufficient ranging opportunities and guarantee low probability of false detection. Each derived sequence has low peak to average power ratio (PAPR) and cross-correlations with other sequences. These properties enable a mobile receiver to easily detect multiple ranging sequences and estimate the corresponding time offsets. Our approach leads to improved performance and enhanced robustness against multi-user interference and multi-path fading. Numerical results verify the effectiveness of the proposed method and its advantages over the class of pseudo-random binary sequences (PRBS) .