Sen-Hung Wang

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Selected mapping (SLM) schemes are commonly employed to reduce the peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It has been shown that the computational complexity of the traditional SLM scheme can be substantially reduced by adopting conversion vectors obtained by using the inverse fast Fourier transform(More)
The cell search procedure of the third generation partnership project long term evolution (3GPP LTE) includes the time synchronization, the frequency synchronization of frames, and the acquisition of cell identity (Cell ID). The traditional cell search scheme detects the Cell ID by computing the correlation between the received signal and all transmitted(More)
The multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with space-frequency block coding (SFBC) is an attractive technique due to its robustness for time selective fading channels. However, the SFBC MIMO-OFDM system also inherits from OFDM systems the drawback of high peak-to-average power ratio (PAPR) of the(More)
A Gaussian integer is a complex number whose real and imaginary parts are both integers. Meanwhile, a sequence is defined as perfect if and only if the out-of-phase value of the periodic autocorrelation function is equal to zero. This paper presents two novel classes of perfect sequences constructed using two groups of base sequences. The nonzero elements(More)
In this paper, we consider the infrastructure mode wireless machine-to-machine (M2M) network, such as the machine-type communication (MTC) in the LTE-Advanced, where there could be tens of thousands of machines within a macro cell and intending to access the same macro base station. Since most of the M2M communications are of low duty cycle and the machine(More)
The computational complexity and peak-to-average power ratio (PAPR) of conventional precoded orthogonal frequency division multiplexing (OFDM) systems can be reduced using a T-OFDM precoded system based on the Walsh-Hadamard matrix. The present paper proposes a novel precoding scheme for further reducing the computational complexity and PAPR of T-OFDM. In(More)
Multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems with spacefrequency block coding (SFBC) have a high computational complexity since the number of inverse fast Fourier transforms (IFFTs) required scales in direct proportion to the number of antennas at the transmitter. This paper proposes to generate the SFBC(More)
High peak-to-average power ratio (PAPR) of the transmitted signals is a major drawback of orthogonal frequency division multiple access (OFDMA) systems. The selected mapping (SLM) method is one of the major schemes employed for PAPR reduction. Unfortunately, the computational complexity of traditional SLM scheme is relatively high since a number of inverse(More)