Abstract
Cognitive radio has been recently proposed as a promising technology to improve the spectrum utilization. In this paper, we consider a system where a licensed radio spectrum is shared by a primary network and a secondary network. Based on the subspace theory, a novel low-complexity algorithm for secondary user selection has been proposed. On the basis of the scheduling scheme, we jointly consider transmit beamforming, scheduling and power allocation, and subsequently present a complete set of solution for secondary network downlink. Simulation results has shown that our proposed scheme not only can limit the introduced interference at primary users within the tolerable range, but also can achieve high sum-rate throughput of secondary network, simultaneously. Furthermore, as is proved by simulation results, our scheme is very robust due to the fact that only a little tolerable performance drop is introduced when simple but nonoptimal equal power allocation is adopted.
Similar content being viewed by others
References
Mitola J, Maguire G Q. Cognitive radio: making software radios more personal. IEEE Pers Commun, 1999, 6(4): 13–18
Telatar E. Capacity of multi-antenna Gaussian channels. Eur Trans Telecommun, 1999, 10(6): 585–596
Foschini G J, Gans M J. On limits of wireless communications in a fading environment when using multiple antennas. Wireless Pers Commun, 1998, 6(3): 311–335
Jindal N, Goldsmith A. Dirty-paper coding versus TDMA for MIMO broadcast channels. IEEE Trans Inf Theory, 2005, 51(5): 1783–1794
Sharif M, Hassibi B. A comparison of time-sharing, DPC, and beamforming for MIMO broadcast channels with many users. IEEE Trans Commun, 2007, 55(1): 11–15
Costa M. Writing on dirty paper. IEEE Trans Inf Theory, 1983, 29(3): 439–441
Weingarten H, Steinberg Y, Shamai S. The capacity region of the Gaussian MIMO broadcast channel. In: IEEE ISIT’04, Chicago, Illinois, 2004. 174
Yoo T, Goldsmith A. On the optimality of multiantenna broadcast scheduling using zero-forcing beamforming. IEEE JSAC, 2006, 24(3): 528–541
Hamdi K, Zhang W, Letaief K B. Joint beamforming and scheduling in cognitive radio networks. In: IEEE GLOBECOM’ 07, Washington, DC, USA, 2007. 2977–2981
Gubner J A, Scharf L L. Detection of subspace waveforms in subspace interference and noise. In: IEEE ICASSP’00, Isstanbul, Turkey, 2000. 309–312
Paulraj A, Nabar R, Gore D. Introduction to Space-time Wireless Communications. Cambridge: Cambridge University Press, 2003
Boyd S, Vandenberghe L. Convex Optimization. Cambridge: Cambridge University Press, 2004
Zhang R, Liang Y C. Exploiting multi-antennas for opportunistic spectrum sharing in cognitive radio networks. In: IEEE PIMRC’07, Athenes, Greece, 2007. 1–5
Author information
Authors and Affiliations
Corresponding author
Additional information
Supported by the National Natural Science Foundation of China (Grant Nos. 60872049, 60871042), the National High-Tech Research & Development Program of China (Grant No. 2007AA10Z235), and the Teaching and Research Finances for the Returned Overseas Chinese Scholars
Rights and permissions
About this article
Cite this article
Xi, W., Yin, C. & Yue, G. Joint beamforming and scheduling in the downlink of cognitive radio networks. Sci. China Ser. F-Inf. Sci. 52, 2324–2331 (2009). https://doi.org/10.1007/s11432-009-0215-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11432-009-0215-5