OFDM for Cognitive Radio Systems: Novel Power Allocation and Bit Loading Algorithms

A novel method to improve the performance of the frequency band is cognitive radio that was introduced in 1999. Due to a lot of advantages of the OFDM, adaptive OFDM method, this technique is used in cognitive radio (CR) systems, widely. In adaptive OFDM, transmission rate and power of subcarriers a...

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Bibliographic Details
Published in:International Journal of Electronics and Telecommunications Vol. 65; no. 1; pp. 139 - 145
Main Authors: Razmi, Shirin, Parhizgar, Naser
Format: Journal Article
Language:English
Published: Warsaw Polish Academy of Sciences 01.01.2019
Subjects:
adaptive modulation
Algorithms
bit loadin
Cognitive radio
Frequencies
Interference
interference constraints
ofdm
Performance enhancement
power allocation
Resource allocation
ISSN:2081-8491, 2300-1933
Online Access:Get full text
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Summary:A novel method to improve the performance of the frequency band is cognitive radio that was introduced in 1999. Due to a lot of advantages of the OFDM, adaptive OFDM method, this technique is used in cognitive radio (CR) systems, widely. In adaptive OFDM, transmission rate and power of subcarriers are allocated based on the channel variations to improve the system performance. This paper investigates adaptive resource allocation in the CR systems that are used OFDM technique to transmit data. The aim of this paper is to maximize the achievable transmission rate for the CR system by considering the interference constraint. Although secondary users can be aware form channel information between each other, but in some wireless standards, it is impossible for secondary user to be aware from channel information between itself and a primary user. Therefore, due to practical limitation, statistical interference channel is considered in this paper. This paper introduces a novel suboptimal power allocation algorithm. Also, this paper introduces a novel bit loading algorithm. In the numerical results sections, the performance of our algorithm is compared by optimal and conventional algorithms. Numerical results indicate our algorithm has better performance than conventional algorithms while its complexity is less than optimal algorithm.
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ISSN:2081-8491
2300-1933
DOI:10.24425/ijet.2019.126294