Channel estimation for a multi-user MIMO-OFDM-IDMA system

The data rates of wireless communication systems operating in a frequency selective background can be improved by using Multiple-Input Multiple-Output (MIMO) in association with Orthogonal Frequency Division Multiplexing (OFDM). The shortcomings of Code Division Multiple Access (CDMA) can be overcome by using Interleave Division Multiple Access (IDMA) which is easily integrated into MIMO systems. IDMA combined with OFDM can be used to implement frequency-selective channels. In this paper we outline the basic principles of an OFDM-IDMA transmitter and receiver followed by simulation results to compare the efficiency of implementing OFDM-IDMA. The performance of our receiver is defined by the simulation results of the energy per bit to noise power spectral density ratio (Eb/N0) and Bit Error Rate (BER). A dramatic decrease in BER is achieved by using the channel decoding and channel estimation techniques proposed. It is found that the OFDM-IDMA system is more effective than just using IDMA or OFDM-CDMA. Thus the whole research is to try and implement a technique that proves to be extremely effective over the already existing techniques.