Một số giải pháp nâng cao dung lượng hệ thống vô tuyến nhận thức đa người dùng
Abstract
In this paper, we study the problem of improving capacity of multiuser OFDM - FDMA cognitive radio (CR) system. We propose new algorithms, namedly Interference Inversion Allocation (IIA) and Quantized-Interference Inversion Allocation (Q-IIA) to allocate subcarrier to users of the multiuser CR system. These techniques allocate subcarrier to users inverserly proportional to its interference to primary user (PU). In addition, we also propose to use windowing technique, a technique being used widely in 802.11 family(WiFi) systems, to multiuser CR system to improve its capacity. The computer simulation is carried out for comparison for three cases of allocation such as IIA, Q-IIA and uniform subcarrier allocation, both with and without windowing. The simulation results show that new algorithms IIA, Q-IIA provide better system capacity than uniform subcarrier allocation does. Among IIA and Q-IIA algorithms, IIA brings system capacity higher than Q-IIA does. Relating windowing technique, the multiuser CR system can achieve much higher capacity (2.6 times)in case of using windowing than without using it, applicable to all IIA, Q-IIA, and uniform subcarrier allocation cases.References
F. C. COMMISSION, “Spectrum Policy Task Force,” Rep.ET Docket, vol.02-135, Nov.2002.
MITOLA, J. AND J. MAGUIRE, G. Q, “Cognitive radio: making softwareradios more personal,” IEEE Pers Commun, vol. 6, no. 4, pp. 13–18,1999.
S. HAYKIN, “Cognitive radio: brain-empowered wireless communications,”IEEE J. Sel. Areas Commun., vol. 23, no. 2, pp. 201–220, 2005.
I. F. AKYILDIZ, W.-Y. LEE, M. C. VURAN, AND S. MOHANTY, “A surveyon spectrum management in cognitive radio networks,” IEEE Commun.Mag., vol. 46, no. 4, pp. 40–48, 2008.
G. BANSAL, M. J. HOSSAIN, AND V. K. BHARGAVA, “Adaptive Power Loadingfor OFDM-Based Cognitive Radio Systems,” in Proc. IEEE Int. Conf.Communications ICC ’07, 2007, pp. 5137–5142.
G. BANSAL, M. J. HOSSAIN, AND V. K. BHARGAVA, “Optimal and Suboptimal Power Allocation Schemes for OFDM-basedCognitive Radio Systems,” IEEE Trans. Wireless Commun., vol. 7,no. 11, pp. 4710–4718, 2008.
G. BANSAL, O. DUVAL, AND F. GAGNON, “Joint Overlay and UnderlayPower Allocation Scheme for OFDM-Based Cognitive Radio Systems,” in Proc. IEEE 71st Vehicular Technology Conf. (VTC 2010-Spring),2010, pp. 1–5.
G. BANSAL, M. J. HOSSAIN, AND V. K. BHARGAVA, “Adaptive Power Loadingfor OFDM-Based Cognitive Radio Systems with Statistical InterferenceConstraint,” IEEE Trans. Wireless Commun., vol. 10, no. 9, pp. 2786–2791, 2011.
P. KALIGINEEDI, G. BANSAL, AND V. K. BHARGAVA, “Power Loading Algorithmsfor OFDM-Based Cognitive Radio Systems with ImperfectSensing,” IEEE Trans. Wireless Commun., vol. 11, no. 12, pp. 4225–4230, 2012.
y. Wang, w. Xu, k. Yang, and j. Lin, “Optimal Energy-EfficientPower Allocation for OFDM-Based Cognitive Radio Networks,” IEEECommun. Lett., vol. 16, no. 9, pp. 1420–1423, 2012.
Y. TACHWALI, B. F. LO, I. F. AKYILDIZ, AND R. AGUSTI, “Multiuser ResourceAllocation Optimization Using Bandwidth-Power Product in CognitiveRadio Networks,” IEEE J. Sel. Areas Commun., vol. 31, no. 3, pp. 451–463, 2013.
S. WANG, M. GE, AND W. ZHAO, “Energy-Efficient Resource Allocationfor OFDM-Based Cognitive Radio Networks,” IEEE Trans. Commun.,vol. 61, no. 8, pp. 3181–3191, 2013.
T. WEISS, J. HILLENBRAND, A. KROHN, AND F. K. JONDRAL, “Mutual interferencein OFDM-based spectrum pooling systems,” in Proc. VTC 2004-Spring Vehicular Technology Conf. 2004 IEEE 59th, vol. 4, 2004, pp.1873–1877.
H. A. MAHMOUD AND H. ARSLAN, “Sidelobes suppression in OFDMbasedspectrum sharing systems using adaptive symbol transition,” IEEECommun. Lett., vol. 12, pp. 133–135, 2008.
Y. ZHANG AND C. LEUNG, “An Efficient Power-Loading Scheme forOFDM-Based Cognitive Radio Systems,” IEEE Trans. Veh. Technol.,vol. 59, no. 4, pp. 1858–1864, 2010.
L.V. TUAN, D. C. HIEU, N. T. HIEU, N. V. KINH, “Investigation of windows effect to power allocation problem in Cognitive Radio Systems,”ICCE, Aug. 2012.
LE VAN TUAN, NGUYEN THANH HIEU, NGUYEN VIET KINH, DINH CHI HIEU, “Full-filling Subcarrier Power Allocation in OFDMA-based Cognitive Radio Systems,”Wireless Engineering Technology, Aug, 2013.
HIEU NGUYEN, GUAN YONG LIANG, HIEU NGUYEN, GUAN YONG LIANG, “Full-filling Algorithm for Power Allocation in OFDM-based Cognitive Radio Systems,”ICICS, Dec.2013.
N. T. HOA, N. T. HIEU, N. V. DUC, G. GELLE, AND H. CHOO, “Second order suboptimal power allocation for ofdm-based cognitive radio systems,” International Conference on Ubiquitous Information Management andCommunication, no. 50, February 2013
IEEE, Standard for Information technology Telecommunications and information exchange between systemsLocal and metropolitan area networks Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Laye (PHY) Specifications, IEEE Std.,2007.
S. VERDU AND TE SUN HAN. 2006. A general formula for channel capacity. IEEE Trans. Inf. Theor.40, 4 (September 2006), 1147-1157.