Secure Speech Communication Using Improved OFDM Scrambler for next Generation Mobile Communication Systems

OFDM scrambling is one of the most popular techniques for secure communication. This paper proposes a new scrambling technique based on random permutation with the pseudo random binary generator to improve the performance of OFDM scrambler. To measure the intelligibility of speech, speech transmission index (STI) and common intelligibility scale (CIS) are used. The Bit Error Rate (BER) and Signal to interference plus noise ratio (SINR) are used to evaluate the performance of the speech. By the measurement of PESQ, the quality of the recovered speech was observed. The simulation result shows that the proposed OFDM scrambler is an efficient technique for achieving high data security in 4G broadband wireless communication.