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Secure User Pairing and Power Allocation for Downlink Non-Orthogonal Multiple Access against External Eavesdropping.

Yuxuan Li1, Yanqiu Chen1, Xiaopeng Ji1

  • 1School of Electronics and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.

Entropy (Basel, Switzerland)
|January 22, 2024
PubMed
Summary

We introduce a secure strategy for user pairing and power allocation in Non-Orthogonal Multiple Access (NOMA) systems to maximize the sum secrecy rate. This method enhances security and performance compared to traditional systems.

Keywords:
NOMAexternal eavesdroppingpower allocationsecure communicationuser pairing

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Area of Science:

  • Wireless communication systems
  • Information security
  • Optimization techniques

Background:

  • Non-Orthogonal Multiple Access (NOMA) systems face security challenges due to external eavesdroppers.
  • Optimizing user pairing (UP) and power allocation (PA) is crucial for secure data transmission.
  • Mixed Integer Nonlinear Programming (MINLP) problems in NOMA are computationally complex.

Purpose of the Study:

  • To develop a secure user pairing and power allocation strategy for downlink NOMA systems.
  • To maximize the achievable sum secrecy rate (ASSR) under user rate constraints.
  • To address the complexity of MINLP problems in secure NOMA systems.

Main Methods:

  • Decomposition of the optimization problem into sub-problems for PA and UP.
  • Derivation of closed-form solutions for PA and UP in simplified NOMA systems.
  • Extension of the solution to general 2K-user NOMA systems.

Main Results:

  • The proposed UP and PA strategy achieves optimal ASSR while meeting minimum rate constraints.
  • Numerical simulations validate the theoretical findings.
  • The method outperforms random UP and standard Orthogonal Multiple Access (OMA) systems.

Conclusions:

  • The proposed secure UP and PA strategy effectively enhances ASSR in NOMA systems.
  • Increasing the number of user pairs provides additional performance gains.
  • The strategy offers a practical solution for secure and efficient NOMA communication.