Abstract

with the introduction of new standards at a fast pace, wireless communication is experiencing great development and growth, thereby raising the level of demand for radio spectrum. The spectrum, however, is a limited resource and cannot be subdivided indefinitely to satisfy any use. As a result, spectrum scarcity arises. This scarcity represents the main problem that faces the future of wireless networks. This scarcity is due to the inefficient fixed spectrum allocation technique. The Dynamic Spectrum Access (DSA) is a successful solution to reduce the spectrum scarcity that wireless communications currently face. DSA allows users without a spectrum license known as Secondary Users (SUs) to temporarily use the unused licensed spectrum. This work focuses on analysis, and design of the Cognitive Radio (CR) system forOrthogonal Frequency Division Multiplexing modulation. The OFDM transceiver system has been implemented in the first stage using the Quadrature Phase Shift Keying (QPSK) modulation technique by Xilinx System Generator Inter-Symbol InterferenceSimulink (XSG) based on MATLAB. The second stage of the proposed system is to design energy detection of the OFDM transceiver. This system was analyzed under the Adaptive White Gaussian Noise (AWGN) channel based XSG. In this work, the energy detector is also designed using the XSG ISE14.1 Simulink and obtained all the signals successfully. Index Terms— CR, Spectrum Sensing, OFDM, QPSK, ED, AWGN.

Highlights

  • Wireless networks are increasing at an exponential pace, requiring a greater and larger radio spectrum for cellular communications

  • 8 shows the sub- system of serial to parallel, which is used to convert the data received from the OFDM transmitter to parallel form. the output signal is taken after 16 clock puls

  • Several points that deal with the nature of cognitive adaptive radio systems can be inferred

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Summary

INTRODUCTION

Wireless networks are increasing at an exponential pace, requiring a greater and larger radio spectrum for cellular communications. Applying the OFDM to cognitive radio would bring advantages in shaping the spectrum to make it easier for the secondary user to access the available spectrum and increase the performance of the spectrum use of the entire system[2]. A process, which known as Frequency Division multiplexing, divides the spectrum available into a number of sub-bands, which are transmitted in parallel by multiple channels (carriers). It combines a large number of low data rate carriers to create a composite high data rate communication system[4, 5]. Look at the spectrum efficiency and energy efficiency that OFDM-based Cognitive Radio (CR) networks can offer to wireless systems.

Spectrum sensing
Spectrum decision
XSG SIMULATION RESULT
CONCLUSION
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