Abstract
The focus of this paper is to find a robust power control strategy with uncertain noise plus interference (NI) in cognitive radio networks (CRNs)in an under orthogonal frequency-division multiplexing (OFDM) framework. The optimization problem is formulated to maximize the data rate of secondary users (SUs) under the constraints of transmission power of each SU, probabilistic the transmit rate of each SU at each subcarrier and robust interference constraint of primary user. In consideration of the feedback errors from the quantization due to uniform distribution, the probabilistic constraint is transformed into closed forms. By using Lagrange relaxation of the coupling constraints method and subgradient iterative algorithm in a distributed way, we solve this dual problem. Numerical simulation results show that our proposed algorithm is superior to the robust power control scheme based on interference gain worst case approach and non-robust algorithm without quantization error in perfect channels in the improvement of data rate of each SU, convergence speed and computational complexity.
Highlights
In recent decade, the explosive growth of various wireless services has led to the increasing demand for limited radio spectrum
After the analysis of the above literatures, we proposed a probabilistically robust power control (PRPC) algorithm for orthogonal frequency-division multiplexing (OFDM) based cognitive radio networks under noise plus interference uncertainty
In order to alleviate the impact of such uncertainty impacts on the cognitive radio (CR) system, we guarantee the performance of secondary users (SUs) regarding dki as existing the random variable by power allocation to maximize their data rate for all subcarriers, i.e
Summary
The explosive growth of various wireless services has led to the increasing demand for limited radio spectrum. In [11,12], transmit power and data rate allocation algorithms are presented based on the lower bound of the signal-to-interference-plus-noise ratio (SINR) of each SU. The interference uncertainty in the channel is often not considered, which will increase the outage probability of users in CRNs. In underlay CRNs, a robust distributed uplink power allocation algorithm to maximize the social utility of SUs is presented in [14], when the interference from PUs to the base station of SUs is uncertain. After the analysis of the above literatures, we proposed a probabilistically robust power control (PRPC) algorithm for OFDM based cognitive radio networks under noise plus interference uncertainty.
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