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A novel sample based quadrature phase shift keying demodulator.

Mohamed Moubark A, Ali SH - ScientificWorldJournal (2014)

Bottom Line: A software simulation of the proposed design was successfully carried out using MATLAB Simulink software platform.In the conventional system, at least 10 dB signal to noise ratio (SNR) is required to achieve the bit error rate (BER) of 10(-6), whereas, in the proposed technique, the same BER value can be achieved with only 5 dB SNR.Since some of the power consuming elements such as voltage control oscillator (VCO), mixer, and low pass filter (LPF) are no longer needed, the proposed QPSK demodulator will consume almost 68.8% to 99.6% less operational power compared to conventional QPSK demodulator.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical, Electronic and Systems Engineering, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.

ABSTRACT
This paper presents a new practical QPSK receiver that uses digitized samples of incoming QPSK analog signal to determine the phase of the QPSK symbol. The proposed technique is more robust to phase noise and consumes up to 89.6% less power for signal detection in demodulation operation. On the contrary, the conventional QPSK demodulation process where it uses coherent detection technique requires the exact incoming signal frequency; thus, any variation in the frequency of the local oscillator or incoming signal will cause phase noise. A software simulation of the proposed design was successfully carried out using MATLAB Simulink software platform. In the conventional system, at least 10 dB signal to noise ratio (SNR) is required to achieve the bit error rate (BER) of 10(-6), whereas, in the proposed technique, the same BER value can be achieved with only 5 dB SNR. Since some of the power consuming elements such as voltage control oscillator (VCO), mixer, and low pass filter (LPF) are no longer needed, the proposed QPSK demodulator will consume almost 68.8% to 99.6% less operational power compared to conventional QPSK demodulator.

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Buffer redistributes the incoming samples into 2 sets of samples.
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fig3: Buffer redistributes the incoming samples into 2 sets of samples.

Mentions: The series of polarities samples need to be changed into a parallel of 4 × 1 matrixes so that it can be compared with each of the group data stored inside the LUT. A buffer with output size of four elements is used to redistribute the pulses from the sign block. Each pulse with positive and negative polarity has ts period and needs to be grouped into four elements with period of T as given by(5)T=4ts, s=1⋯∞.This is crucial since only four complete pulses which have period equal to T can determine a combinational group of data represented by the QPSK signal. Figure 3 shows an example on how the buffer redistributes the received data.


A novel sample based quadrature phase shift keying demodulator.

Mohamed Moubark A, Ali SH - ScientificWorldJournal (2014)

Buffer redistributes the incoming samples into 2 sets of samples.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4150515&req=5

fig3: Buffer redistributes the incoming samples into 2 sets of samples.
Mentions: The series of polarities samples need to be changed into a parallel of 4 × 1 matrixes so that it can be compared with each of the group data stored inside the LUT. A buffer with output size of four elements is used to redistribute the pulses from the sign block. Each pulse with positive and negative polarity has ts period and needs to be grouped into four elements with period of T as given by(5)T=4ts, s=1⋯∞.This is crucial since only four complete pulses which have period equal to T can determine a combinational group of data represented by the QPSK signal. Figure 3 shows an example on how the buffer redistributes the received data.

Bottom Line: A software simulation of the proposed design was successfully carried out using MATLAB Simulink software platform.In the conventional system, at least 10 dB signal to noise ratio (SNR) is required to achieve the bit error rate (BER) of 10(-6), whereas, in the proposed technique, the same BER value can be achieved with only 5 dB SNR.Since some of the power consuming elements such as voltage control oscillator (VCO), mixer, and low pass filter (LPF) are no longer needed, the proposed QPSK demodulator will consume almost 68.8% to 99.6% less operational power compared to conventional QPSK demodulator.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical, Electronic and Systems Engineering, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.

ABSTRACT
This paper presents a new practical QPSK receiver that uses digitized samples of incoming QPSK analog signal to determine the phase of the QPSK symbol. The proposed technique is more robust to phase noise and consumes up to 89.6% less power for signal detection in demodulation operation. On the contrary, the conventional QPSK demodulation process where it uses coherent detection technique requires the exact incoming signal frequency; thus, any variation in the frequency of the local oscillator or incoming signal will cause phase noise. A software simulation of the proposed design was successfully carried out using MATLAB Simulink software platform. In the conventional system, at least 10 dB signal to noise ratio (SNR) is required to achieve the bit error rate (BER) of 10(-6), whereas, in the proposed technique, the same BER value can be achieved with only 5 dB SNR. Since some of the power consuming elements such as voltage control oscillator (VCO), mixer, and low pass filter (LPF) are no longer needed, the proposed QPSK demodulator will consume almost 68.8% to 99.6% less operational power compared to conventional QPSK demodulator.

Show MeSH