A Study on Data Spread OFDM using LDPC Codes

Abstract

In the communication systems using OFDM, it is necessary to compensate influence of frequency selective fading caused by multi-path. An error correcting code is one of the effective methods and it is adopted in many systems using OFDM. The method that spreads data symbols in frequency domain is one of the effective methods. In the OFDM signal generated by this procedure, the original data symbols are spread over the whole carriers, coded data spread OFDM scheme. By spreading data symbols over whole carriers, it is possible to recover data symbols even if some carriers are lost under severe frequency selective fading. Though data spread OFDM itself is very effective scheme to improve characteristics under frequency selective fading without loss of data transmission rate, it is possible to improve bit error rate characteristic further by using the LDPC code.