The goal of future wireless communication is to provide high quality wireless multimedia services so that data with high rate can be transmitted reliably. Recent information on theoretic research has shown that Multiple Input Multiple Output (MIMO) systems can achieve enormous spectral efficiency. The use of multiple antennas allows an independent channel to be created in the space and is the most interesting and promising wireless research area. The use of multiple antennas at both ends of a wireless link holds the potential to drastically improve the spectral efficiency and link reliability in future wireless communications systems. It seems to be a promising candidate for the next generation. In this paper, two techniques for the next 4G system—OFDM and CDMA—are compared with respect to their error performance in multiuser environment. The studies of both transmission techniques are performed for MIMO architecture. This paper provides a comparison of OFDM and CDMA-based MIMO technique.

The major challenges to future wireless communication system design are increased spectral efficiency and improved link reliability. The wireless channel is nothing but a propagation medium which suffers from fading and interference from other users. We know that common forms of diversity are time diversity (due to Doppler spread) and frequency diversity (due to delay spread). Nowadays, the use of spatial (or antenna) diversity is becoming more and more popular because it can be provided without loss in spectral efficiency. Receive diversity, which is the use of multiple antennas on the receive side of a wireless link, is a well-studied subject. Driven by mobile wireless applications, where it is difficult to deploy multiple antennas in the handset, the use of multiple antennas on the transmit side, combined with signal processing and coding, has become known as space-time coding and is currently an active area of research. By using multiple antennas at both ends of a wireless link, one can easily demonstrate the potential of achieving extraordinary data rates. This technology of using multiple antennas is known as spatial multiplexing (Wolniansky et al.,1998) or BLAST (Golden et al., 1999) that exhibits an impressive increase in the spectral efficiency.

Besides spatial diversity, the broadband Multiple Input Multiple Output (MIMO) channel offers higher capacity and frequency diversity due to delay spread. Orthogonal Frequency Division Multiplexing (OFDM) can reduce the receiver complexity significantly in wireless broadband systems. Therefore, the use of MIMO technology in combination with OFDM, i.e., MIMO-OFDM, seems to be an attractive solution for future broadband wireless systems. The objective of this paper is to provide comparison and analysis of OFDM and CDMA-based MIMO architecture and their performance with Multi-User Detection (MUD).

Telecommunications Journal, Code Division Multiple Access, CDMA, Orthogonal Frequency Division Multiplexing, OFDM, Vertical Bells Labs Layered Space-Time Architecture, V-BLAST, Multi-User Detection, MUD, Multiple Input Multiple Output, MIMO, Single Network Frequency, SFN, Inverse Fast Fourier Transform, IFFT, Inter-Symbol-Interference, ISI, Inverse Fast Fourier Transform, IFFT.