Power consumption estimation has been conducted for the proposed design based on the power consumed by individual components obtained from literature as shown in Table 4. For each one of the components, maximum and a minimum values are taken into consideration from various references so that it will give a rough idea for the total power consumption that can be expected.
The following calculation shows the maximum and minimum power consumption for the proposed design:. It can be seen that the power consumption of the proposed design is between 0. The reduction of the power consumption is between A novel architecture for QPSK demodulator has been proposed and demonstrated promising results.
The results obtained for both demodulation schemes do not include any error correction coding, phase, and frequency error detection technique. This indirectly eliminates the use of VCO, a component that contributes to the phase and frequency distortion. The new architecture consumes almost On top of that, the proposed design is also expected to consume As for future work, channel selection method, error correction coding, and signal locking mechanism for sampling starting time will be included to further evaluate the proposed architecture.
Hardware implementation on Virtex 6 FPGA board has been planned for performance measurement and verification. The authors declare that there is no conflict of interests regarding the publication of this paper. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Received 13 Apr Revised 21 Jul Accepted 22 Jul Published 14 Aug Introduction Quadrature Phase Shift Keying QPSK is a modulation scheme commonly used in wireless communication system due to its ability to transmit twice the data rate for a given bandwidth [ 1 ]. Figure 1. Table 1. Figure 2. Figure 3. Buffer redistributes the incoming samples into 2 sets of samples. Figure 4. Table 2. Table 3. Comparison of power gain between the 3 phases error at BER of.
Figure 5. Figure 6. Samples obtained for phase error and standard QPSK signals from until. Figure 7. Table 4. Power comparison for various components in QPSK demodulator. References D. Master Easton, J. Snowdon, and D. View at: Google Scholar K. Chen and A. Liu and C. View at: Google Scholar T. Tuli, N. The waveforms at the various stages of the modulator are shown in the Figure 4. The performance simulation for the QPSK transmitter-receiver combination was also coded in the code given above and the resulting bit-error rate performance curve will be same as that of conventional BPSK.
In OQPSK, the orthogonal components cannot change states at the same time, this is because the components change state only at the middle of the symbol periods due to the half symbol offset in the Q-channel. Choice of non-coherent demodulation results in simpler receiver design. Read more about QPSK and its variants, implementation of their modulator and demodulator, performance simulation in these books:. The phase transition properties of the different variants of QPSK schemes, are easily investigated using constellation diagram.
Refer this article that discusses the method to plot signal space constellations, for the various modulations used in the transmitter. Rate this article: 45 votes, average: 3.
COM, PP. Provide your answer by showing calculations. Rayleigh channel used BER curves to show performance…plz i need it urgently…. So my solution for you is at first upsample of your NRZ data arbiary 4,8 or 16 , … and then taking convolution of upsampled data and root raised cosine filter will have give simply the output that you need.
Becasue simply there is more bits to be wrong. But in the cost that your bit rate is the smallest possible in your system. Please check page in the PDF version. I just bought the ebook and copied the same code for the two m files.
I got the same error message. Can you check whether the code in your file declares the following on line 11, just before the switch statement on line 12 as shown below?
I mean, in the program provided by you, I changed one of the input parameter in NRZEncoder function from polar to unipolar. If you use unipolar encoding the constellations in trasmitter and receiver will be different. QPSK modulation has to be simulated with polar encoding. Because of that your bits are detected wrongly. In QPSK, the inphase component is multiplied by cos and quadrature component by sine.
So there is no problem here. But when you use unipolar encoding, the inphase or quadrature phase components take value 0 or 1. It is not recommended to use unipolar encoding for QPSK modulation as it defeats the basic architecture of the modulation itself.
I tried this code using unipolar and polar line coding. With polar coding, the reconstructed bit sequence was okay. Can anyone tell me the reason for this behaviour?
For this purpose, a NRZ encoder is used. I am trying to understand this program. I unable to understand what is the need for NRZ encoder. Following is the block diagram for the same. The QPSK waveform for two-bits input is as follows, which shows the modulated result for different instances of binary inputs. The QPSK Demodulator uses two product demodulator circuits with local oscillator, two band pass filters, two integrator circuits, and a 2-bit parallel to serial converter. Following is the diagram for the same.
The two product detectors at the input of demodulator simultaneously demodulate the two BPSK signals.
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