Other than the conventional fast Fourier transform (FFT) for multicarrier modulation, a new approach for multicarrier modulation (MCM) has been known. Meanwhile, multicarrier modulation involves dividing the broadband channel into many orthogonal but overlapping narrowband carriers. In an OFDM modulation based multicarrier system using the FFT, a cyclic prefix (CP) is inserted after each symbol frame to combat the effects of inter symbol interference (ISI). By inserting the CP, which results in spectral inefficiency OFDM schemes trades up to 25% of the transmit bandwidth. A new MCM approach that is void of the expense is the wavelet transform-based systems. These systems also have very suppressed side-lobes and exhibit improved BER performance. In wavelet based systems, the latest challenge in its implementation is in the channel estimation. In this work we have studied the performance of the FFT based OFDM system against wavelet transform (WT) based multicarrier system using a simple zero forcing (ZF) equalization in time domain. The studied system shows some improved BER performance.

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This paper studies the effect of nonlinear and linear crosstalk in a MIMO (multiple in, multiple out) transceiver. These effects are mainly due to the power amplifier (PA) nonlinear behaviour and mutual coupling of antennas in the MIMO transmitter. The effects of the crosstalk interference on the signal performance are studied based on the measured error vector magnitude (EVM) at the transmitting antennas. The simulation and measurement results show that PA nonlinearity and RF crosstalk need to be considered in the design process.

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