In this paper, we consider a distributed beamforming scheme (DBF) in a spectrum sharing system where multiple secondary users share the spectrum with some licensed primary users under an interference temperature constraint. We assume that the DBF is applied at the secondary users. We first consider optimal beamforming and compare it with the user selection scheme in terms of the outage probability and bit error rate performance metrics. Since perfect feedback is difficult to obtain, we then investigate a limited feedback DBF scheme and develop an analysis for a random vector quantization design algorithm. Specifically, the approximate statistics functions of the squared inner product between the optimal and quantized vectors are derived. With these statistics, we analyze the outage performance. Furthermore, the effects of channel estimation error and number of primary users on the system performance are investigated. Finally, optimal power adaptation and cochannel interference are considered and analyzed. Numerical and simulation results are provided to illustrate our mathematical formalism and verify our analysis. © 2012 IEEE.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported in part by the National Priorities Research Program (NPRP) under Grant #08-152-2-043 and Grant #09-341-2-128 from the Qatar National Research Fund (a member of Qatar Foundation) and in part by the National Natural Science Foundation of China under Grant 61071114. The review of this paper was coordinated by Dr. S. Sun.
ASJC Scopus subject areas
- Automotive Engineering
- Applied Mathematics
- Computer Networks and Communications
- Electrical and Electronic Engineering
- Aerospace Engineering