Mutual interference considered power allocation in OFDM-based cognitive networks: The single SU case

  • Authors:

  • Chengshi Zhao;Mingrui Zou;Kyungsup Kwak

  • Affiliations:

  • Wireless Network Lab, School of Information and Communications Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China and Telecommunications Engineering Lab, Gradua ...;Telecommunications Engineering Lab, Graduate School of IT and Telecommunications, Inha University, Incheon 402-751, Republic of Korea;Telecommunications Engineering Lab, Graduate School of IT and Telecommunications, Inha University, Incheon 402-751, Republic of Korea

  • Venue:
  • Computer Communications
  • Year:
  • 2009

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Abstract

Efficient and conflict-free power allocation strategies in cognitive radio networks are being extensively studied in current research in order to meet the requirements of future wireless applications. In this paper, specifying the single secondary user (SU) with multiple primary user (PU) case, a novel power allocation scheme is developed for orthogonal frequency division multiplexing (OFDM) - based cognitive radio networks designed to maximize the capacity of the SU while limiting the interference to the PUs. First, the mutual interference between the SU and the PUs is comprehensively formulated as the restrictions on the SU's transmission power. Secondly, the power allocation problem is analyzed and formulated as a constrained optimization problem which is concluded to a peak-power constrained water-filling formulation. Finally, a novel low-complexity water-filling algorithm is proposed to solve the optimization problem and the optimal power allocation result is achieved. In a simplified scenario, numerical results are exhibited to confirm the efficiency of the proposed water-filling algorithm, and the influence of the mutual interference on the power allocation and the system capacity is further illustrated.