Joint Subcarrier and Bit Allocation for Secondary User with Primary Usersﾂ｡ﾂｯ Cooperation

• Xiaorong Xu,
• Yu-Dong Yao,
• Sanqing Hu,
• Yingbiao Yao,

Vol. 7, No. 12, December 28, 2013
10.3837/tiis.2013.12.005, Download Paper (Free):

• Primary users’ cooperation (PU Coop)
• Joint subcarrier and bit allocation
• Signal to interference plus noise ratio (SINR)
• Arith-metric geo-metric (AM-GM) inequality
• Interference power level

Abstract

Interference between primary user (PU) and secondary user (SU) transceivers should be mitigated in order to implement underlay spectrum sharing in cognitive radio networks (CRN). Considering this scenario, an improved joint subcarrier and bit allocation scheme for cognitive user with primary users cooperation (PU Coop) in CRN is proposed. In this scheme, the optimization problem is formulated to minimize the average interference power level at the PU receiver via PU Coop, which guarantees a higher primary signal to interference plus noise ratio (SINR) while maintaining the secondary user total rate constraint. The joint optimal scheme is separated into subcarrier allocation and bit assignment in each subcarrier via arith-metric geo-metric (AM-GM) inequality with asymptotical optimization solution. Moreover, the joint subcarrier and bit optimization scheme, which is evaluated by the available SU subcarriers and the allocated bits, is analyzed in the proposed PU Coop model. The performance of cognitive spectral efficiency and the average interference power level are investigated. Numerical analysis indicates that the SUs spectral efficiency increases significantly compared with the PU non-cooperation scenario. Moreover, the interference power level decreases dramatically for the proposed scheme compared with the traditional Hughes-Hartogs bit allocation scheme.

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