Abstract
In this paper, the covert performance of the non-orthogonal multiple access (NOMA) system with random transmit power under hardware impairments over the Nakagami fading channel is investigated, where the stronger user serves as a covert user (Bob) and receives the secure message from the transmitter (Alice) under the cover of the weaker user (Carl). The transmission is monitored by a warden (Willie). To improve the covert performance, we randomize the transmit power of Alice, which is subject to a uniform distribution. Based on this, considering the randomness of covert user's position, we derive the closed-form expressions of the average detection error probability (ADEP) respectively for the warden with instantaneous and statistical channel information. Then, the optimal detection threshold based on one-dimensional (1D) search method is presented for minimizing the ADEP. To simplify the optimal threshold, the suboptimal threshold with low complexity is also derived. Besides, the outage probability (OP) of the system is deduced for performance analysis and optimization. Under the constraints of covertness and reliability, the power allocation (PA) coefficient is optimized to minimize the OP of the covert user, and the 1D search scheme is proposed to obtain the optimal solution. Also, a suboptimal scheme is presented to reduce the complexity of the optimal scheme. Numerical results are presented to validate our theoretical analysis, and show that randomizing the transmit power can effectively improve the covert performance. Moreover, the system with two optimized thresholds can obtain lower ADEP than that with a fixed threshold, and the system with two optimized PA coefficients has a lower OP than that with a fixed PA.
Document Type
Journal Article
Date of Publication
1-1-2025
Volume
24
Issue
4
School
School of Science
Creative Commons License
This work is licensed under a Creative Commons Attribution-No Derivative Works 4.0 License.
Publisher
IEEE
Identifier
Shihao Yan: https://orcid.org/0000-0002-4586-1926
Recommended Citation
Yu, X., Shen, K., Rui, Y., Yan, S., Jia, G., & Guizani, M. (2025). Covert performance of NOMA system with hardware impairments in Nakagami fading channel. DOI: https://doi.org/10.1109/TWC.2025.3531642
Comments
This is an an Author's Accepted Manuscript of an article published by IEEE. © 2025 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Yu, X., Shen, K., Rui, Y., Yan, S., Jia, G., & Guizani, M. (2025). Covert performance of NOMA system with hardware impairments in Nakagami fading channel. IEEE Transactions on Wireless Communications, 24(4), 3499-3514. https://doi.org/10.1109/TWC.2025.3531642