Publication Date:
2018-06-05
Description:
Sensors, Vol. 18, Pages 1809: Cooperative Feedback Bits Allocation and Transmit Power Control in Underlay Cognitive Radio Networks Sensors doi: 10.3390/s18061809 Authors: Deokhui Lee Jaewoo So In this paper, we consider an underlay cognitive radio network where the spectrum is shared with the primary network. Due to the coexistence of primary and secondary networks, primary users (PUs) are interfered with by the inter-network interference, at the same time secondary users (SUs) counteract the intra-network (inter-user) interference. Based on the cooperative feedback between the primary network and the secondary network, the secondary transmitter (ST) applies the cognitive beamforming to suppress the interference to PUs while improving the sum rate of SUs. We herein propose an adaptive feedback bits allocation among multiple PUs and SUs where the quantized channel direction information (CDI) for the interference channel is forwarded to the ST in order to utilize the beamforming. Moreover, based on the cognitive beamforming, we adjust the transmit power of the ST under the constraint of the average interference at PUs. To jointly solve the feedback bits allocation and the transmit power control problems, we formulate an optimization problem which requires a little iterations compared with the separated feedback bits allocation and the transmit power control problems. Numerical results show that the proposed scheme significantly improves the sum rate of SUs while satisfying the average interference constraint at PUs.
Electronic ISSN:
1424-8220
Topics:
Chemistry and Pharmacology
,
Electrical Engineering, Measurement and Control Technology
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