11th IEEE Symposium on Computers and Communications (ISCC'06)
New Spreading Codes for MC-CDMA and OFDM Systems
Cagliari, Sardinia, Italy
June 26-June 29
ISBN: 0-7695-2588-1
Khoirul Anwar, Nara Institute of Science and Technology (NAIST), Japan
Masato Saito, Nara Institute of Science and Technology (NAIST), Japan
Takao Hara, Nara Institute of Science and Technology (NAIST), Japan
Minoru Okada, Nara Institute of Science and Technology (NAIST), Japan
Recently, there is an interest to increase capacity of multicarrier code division multiplexing (MC-CDMA) and orthogonal frequency division multiplexing (OFDM) by using spreading codes. Some spreading codes only support up to K = N+M, where M \le N. In this paper, we propose a new spreading code with low cross correlation and high autocorrelation while capable of supporting K = 2N+1 users. It means that 2N+1 users or data symbols are able to be transmitted over only N subcarriers. The numerical results show that our proposed code outperforms current Pseudo- Orthogonal Carrier Interferometry (POCI) code with gain of 3dB in additive white Gaussian noise (AWGN) channel and more than 4dB in multipath fading channel at bit-error-rate (BER) level of 10-5. By the proposed code, peak-to-average power ratio (PAPR) problem as a typical problem in multicarrier system is also able to be reduced up to the PAPR level of single carrier system (with roll-of-factor=0.10).
Citation:
Khoirul Anwar, Masato Saito, Takao Hara, Minoru Okada, Heiichi Yamamoto, "New Spreading Codes for MC-CDMA and OFDM Systems," iscc, pp.283-288, 11th IEEE Symposium on Computers and Communications (ISCC'06), 2006