Improving Jain Fairness Index and Optimizing Transmitter Power Consumption in NOMA Systems.

Document Type : Original Article

Authors

Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran

Abstract

In this paper, an approach is proposed for power allocation in Non-orthogonal multiple access (NOMA) systems in downlink to achieve user fairness from user capacity perspective and to optimize transmitter power consumption as well. In recent works, researchers have defined optimization problems and solved them, as in a method called Fair-NOMA, to maximize the capacity of each user in NOMA compared to OMA but the difference between the capacity of users and optimizing the transmitter power consumption are not considered. In this paper, a NOMA system with 2 and more than 2 users in downlink is considered. In the 2-user scenario by equating capacities of users, the Jain fairness index is maximized, fairness is achieved in transmitter power consumption and the difference between the capacities of users is eliminated. In addition, computer simulations show that the capacity of the user with weaker channel gain improves noticeably. Moreover, in a NOMA system with more than 2 users a fixed power coefficient is allocated to the user with the weakest channel condition, and power allocation to the other users is done in a way that the transmitter power consumption is optimized. Computer simulations is carried out to verify the effectiveness of the suggested methods.

Keywords


[1] محمد لاری، »تخصیص منابع جهت کمینه‌سازی تأخیر ارسال در سامانه‌های مخابراتی تغذیه شونده به‌صورت بی‌سیم«، مجله مهندسی برق دانشگاه تبریز، دوره 47، شماره 3، صفحات 1205-1212، پاییز 1396.
[2] عزیزالله بهمنی و مهرزاد بیغش، »کنترل توان توامان در شبکه مخابرات رله‌ای با چندین منبع فرستنده و گیرنده، به روش تقویت و ارسال و با در نظر گرفتن مسیر مستقیم«، مجله مهندسی برق دانشگاه تبریز، دوره 48، شماره 3، صفحات 1011-1024، پاییز 1397.
[3] F. Liu, P. Mähönen, and M. Petrova, “Proportional fairness-based power allocation and user set selection for downlink NOMA systems,” in IEEE International Conference on Communications (ICC), pp. 1-6, 2016.
[4] P. Wang, J. Xiao, and P. L, “Comparison of orthogonal and non-orthogonal approaches to future wireless cellular systems,” IEEE Vehicular Technology Magazine, vol. 1, no. 3, pp. 4-11, 2006.
[5] J. Schaepperle and A. Rüegg, “Enhancement of throughput and fairness in 4G wireless access systems by non-orthogonal signaling,” Bell Labs Technical Journal, vol. 13, no. 4, pp. 59-77, 2009.
[6] J. Schaepperle, “Throughput of a wireless cell using superposition based multiple-access with optimized scheduling,” in 21st Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, pp. 212-217, 2010.
[7] T. Takeda and K. Higuchi, “Enhanced User Fairness Using Non-Orthogonal Access with SIC in Cellular Uplink,” in IEEE Vehicular Technology Conference (VTC Fall), pp. 1-5, 2011.
[8] S. Tomida and K. Higuchi, “Non-orthogonal access with SIC in cellular downlink for user fairness enhancement,” in International Symposium on Intelligent Signal Processing and Communications Systems (ISPACS), pp. 1-6, 2011.
[9] B. Kimy, S. Lim,  H. Kim, S. Suh, J. Kwun, S. Choi, C. Lee, S. Lee, and D. Hong,“Non-orthogonal Multiple Access in a Downlink Multiuser Beamforming System,” in IEEE Military Communications Conference  (MILCOM), pp. 1278-1283, 2013.
[10] J. Choi, “Minimum Power Multicast Beamforming With Superposition Coding for Multiresolution Broadcast and Application to NOMA Systems,” IEEE Transactions on Communications, vol. 63, no. 3, pp. 791-800, 2015.
[11] Q. Sun, S. Han, I. C. L, and Z. Pan, “On the Ergodic Capacity of MIMO NOMA Systems,” IEEE Wireless Communications Letters, vol. 4, no. 4, pp. 405-408, 2015.
[12] M. Al-Imari, P. Xiao, M. A. Imran, and R. Tafazolli, “Uplink non-orthogonal multiple access for 5G wireless networks,” in 11th International Symposium on Wireless Communications Systems (ISWCS), pp. 781-785, 2014.
[13] F. Liu, P. Mähönen, and M. Petrova, “Proportional fairness-based user pairing and power allocation for non-orthogonal multiple access,” in IEEE 26th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), pp. 1127-1131, 2015.
[14] S. Timotheou and I. Krikidis, “Fairness for Non-Orthogonal Multiple Access in 5G Systems,” IEEE Signal Processing Letters, vol. 22, no. 10, pp. 1647-1651, 2015.
[15] Z. Ding, P. Fan, and H. V. Poor, “Impact of User Pairing on 5G Nonorthogonal Multiple-Access Downlink Transmissions,” IEEE Transactions on Vehicular Technology, vol. 65, no. 8, pp. 6010-6023, 2016.
[16] J. A. Oviedo and H. R. Sadjadpour, “A Fair Power Allocation Approach to NOMA in Multiuser SISO Systems,” IEEE Transactions on Vehicular Technology, vol. 66, no. 9, pp. 7974-7985, 2017.
[17] M. Köppen, K. Ohnishi, and M. Tsuru, “Multi-Jain Fairness Index of Per-Entity Allocation Features for Fair and Efficient Allocation of Network Resources,” in 5th International Conference on Intelligent Networking and Collaborative Systems, pp. 841-846, 2013.
[18] J. A. Oviedo and H. R. Sadjadpour, “A new NOMA approach for fair power allocation,” in IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS), pp. 843-847, 2013.