Performance Analysis of ZF and MMSE Channel Equalizer for Butterworth and Chebyshev Low Pass Channels

Due to the high demand for information in the communication system needs a greater amount of data transmission on the current channels. The data flow rate on the existing channel is bounded because of the Inter Symbol Interference (ISI). To minimize the influence of ISI Channel equalizers are utilized. The Zero Forcing (ZF) & Minimum Mean Square Error (MMSE) equalizer is used to compare the eye diagrams before and after the equalizer in this paper. It shows that the equalizer reduce the ISI effectively and achieves the suitable performance.

MMSE Equalization Based Performance of Chaotic Interleaving Scheme for Iterative IDMA System

Background: In this paper, a chaotic interleaving scheme is proposed for further performance improvement of Interleave Division Multiple Access (IDMA). Interleavers are used to generate permuted sequence of signals to be transmitted with optimum correlation. Methods: Random interleaving (RI) was the fundamental taxonomy and used to distinguish the different users in IDMA scheme. The logistic map based chaotic interleaving scheme is suggested for IDMA. The system is also combined with Minimum Mean Square Error (MMSE) equalizer to combat the effect of Inter Symbol Interference (ISI). Results: For the sake of simplicity, no pulse shaping is assumed at the transmitter and ISI channel is considered to be a fixed 3 tap channel. Simulations are performed in MATLAB. BPSK modulation is used. Furthermore, the results show that the IDMA with proposed logistic map based chaotic interleaver outperforms the traditional random interleaving scheme in terms of BER without the need of extra memory and computational complexity. Conclusion: The obtained results show the noticeable performance improvement of CI-IDMA with MMSE equalization in deep fading situations. Chaos based interleaver also offers other advantages such as less requirement of memory and small implementation complexity.

An Enhanced Two Stage MMSE Equalizer for Coded FBMC/OQAM Systems

In this article, the authors investigate the enhanced two stage MMSE (TS-MMSE) equalizer in bit-interleaved coded FBMC/OQAM system which gives a tradeoff between complexity and performance, since error correcting codes limits error propagation, so this allows the equalizer to remove not only ICI but also ISI in the second stage. The proposed equalizer has shown less design complexity compared to the other MMSE equalizers. The obtained results show that the probability of error is improved where SNR gain reaches 2 dB measured at BER compared with ICI cancellation for different types of modulation schemes and ITU Vehicular B channel model. Some simulation results are provided to illustrate the effectiveness of the proposed equalizer.