Paper Performance Analysis of OFDM-IDMA and SC-FDMA-IDMA Scheme in Underwater Communication

Ajay Patel; M. Shukla; Ruchi Gupta

Ajay Patel Department of Electronics Engineering ,Harcourt Butler Technological Institute, Kanpur, India;
M. Shukla Department of Electronics Engineering ,Harcourt Butler Technological Institute, Kanpur, India;
Ruchi Gupta Department of Electronics Engineering , Amity University Uttar Pradesh, Lucknow, India;

Abstract

The IDMA scheme based receiver complexity over multi-path channels is related to the channel length. OFDM-IDMA scheme was
proposed as an alternative to plain IDMA over multi-path channels. OFDM-IDMA scheme inherits most of the merits of OFDM and
IDMA scheme. The key advantage of OFDM-IDMA scheme is that MUD can be realized efficiently with complexity per user, independent of the channel length and the number of users, which is significantly lower than that of other alternatives. Single Carrier
Frequency Division Multiple Access (SC-FDMA-IDMA) scheme structure is achieved by adding Discrete Fourier Transform (DFT)
and inverse DFT (IDFT) blocks at the transmitter and receiver respectively, so SC-FDMA scheme is sometimes referred to as DFTspread or DFT-precoded OFDMA scheme. The transmitter of SC-FDMA scheme uses different subcarriers to transmit information
data as in OFDMA scheme. However SC-FDMA schemes transmit the subcarriers sequentially rather than in parallel. Due to addition of above blocks low PAPR is obtained which is important to increase cell coverage and to prolong the battery lifetime of mobile
terminals. There are no major differences between the BER performance of SC-FDMA-IDMA and OFDM-IDMA schemes, but SCFDMA-IDMA scheme has low PAPR than OFDM-IDMA scheme.