Shanlin Sun

Wavelet packet multicarrier system based on MIMO antennae in AWGN

In order to solve the shortage of wireless resources in next-generation mobile communications, a wavelet packet multicarrier system is built based on multiple input multiple output(MIMO) antennae, which integrates the advantages of multiple antennae channel capacity and the superiority of the translation orthogonality of the wavelet packet basis function. The bit error rate(BER) performance of the proposed system is verified by simulation in AWGN wireless channel, that it has the performance advantage, which provides a reference for physical layer standards in the next generation mobile communications.

Channel Capacity of MIMO Multi-Carrier Modulation in Additive Noise

In this paper, we investigate the capacity of multi-carrier modulation (MCM) system based on multiple input multiple output (MIMO) antennae for single user communications over the additive noise channel. We define a two variable energy spectrum function for each antenna which describes energy distribution in time-frequency-space (T-F-S) subchannels. The general wavelet packet basis functions are employed as sub-carrier to give more flexibility to partition of T-F plane compared with Inverse Fast Fourier Transform and Fast Fourier Transform (IFFT/FFT). The total energy and T-F space constraints are given. Under the prior information of additive noise energy distribution, the water-filling resolution is derived to obtain maximum objective capacity function. Furthermore, the optimal resource distribution in three dimensions space is obtained finally.

A Novel Fault Signal Detection Method

Aiming at the fault signal detection in mechanism system, all phase fast Fourier transform (APFFT) method is proposed for fault detection. The method of APFFT has the outstanding characteristics: the very few power leaks, the zero phase error and the fewer side lobes. So it can resist noise and increase the validity of diagnosis results. Finally, the case of bearing diagnosis is given by using the method of APFFT. The simulation results indicate that APFFT method has better character of fault detection. And it is more robust compared to FFT method. Especially, the power leak based on APFFT is fewer and equal to the square of the power leak based on the conventional FFT. So the APFFT method has the better diagnosis ability.

Performance of wavelet shrinkage maximum likelihood estimator in 3GPP’s spatial channel model based on OFDM system

This paper deals with the estimation of the channel impulse response (CTR) of spatial channel model (SCM) in the third generation partnership project (3GPP) based on orthogonal frequency division multiplexing (OFDM) system. Maximum likelihood estimation (MLE) contains intrinsic noise, and Bayesian minimum mean square error estimation (MMSEE) is expected to have better performance as it exploits prior information about the CIR, which results difficulty of implementation in practice. We propose a new estimator which processes MLE with wavelet shrinkage algorithm. Filtered by quantization and reconstruction functions, the estimate becomes more accurate than MLE. Simulation results validate that wavelet shrinkage maximum likelihood estimation (WMLE) outperforms MLE in terms of accuracy and bit error rate (BER) without prior channel information.