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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.

Show MeSH
Performance comparison of 8S-QPSK and conventional QPSK scheme in additive white Gaussian noise (AWGN) channel with confidence interval and empirical value.
© Copyright Policy - open-access
Related In: Results  -  Collection


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fig4: Performance comparison of 8S-QPSK and conventional QPSK scheme in additive white Gaussian noise (AWGN) channel with confidence interval and empirical value.

Mentions: In this section, the QPSK signal is demodulated with the proposed and conventional demodulator with different levels of SNR starting from −2 dB until as high as 6 dB through AWGN channel. This analysis demonstrates the ability of the proposed architecture to withstand the white Gaussian noise compared to the conventional architecture. To validate the performance of the system a 95% of confidence level of the confidence interval test was used for every simulation. The confidence interval test was carried out by using MATLAB built-in function where it requires data such as BER, the total number of input data, and range of SNR to calculate the interval level and the maximum and minimum number of BER [10, 11]. The data compiled for both demodulation schemes are represented graphically in Figure 4. The exponential curve fit has been used to interpolate the log-log scale dataset so that the graph will resemble the water fall curve shape [12].


A novel sample based quadrature phase shift keying demodulator.

Mohamed Moubark A, Ali SH - ScientificWorldJournal (2014)

Performance comparison of 8S-QPSK and conventional QPSK scheme in additive white Gaussian noise (AWGN) channel with confidence interval and empirical value.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: Performance comparison of 8S-QPSK and conventional QPSK scheme in additive white Gaussian noise (AWGN) channel with confidence interval and empirical value.
Mentions: In this section, the QPSK signal is demodulated with the proposed and conventional demodulator with different levels of SNR starting from −2 dB until as high as 6 dB through AWGN channel. This analysis demonstrates the ability of the proposed architecture to withstand the white Gaussian noise compared to the conventional architecture. To validate the performance of the system a 95% of confidence level of the confidence interval test was used for every simulation. The confidence interval test was carried out by using MATLAB built-in function where it requires data such as BER, the total number of input data, and range of SNR to calculate the interval level and the maximum and minimum number of BER [10, 11]. The data compiled for both demodulation schemes are represented graphically in Figure 4. The exponential curve fit has been used to interpolate the log-log scale dataset so that the graph will resemble the water fall curve shape [12].

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