TY - JOUR T1 - Contemporary Approaches to Mitigate Pilot Contamination in Massive Mimo Systems TT - Büyük Ölçekli Mimo Sistemlerde Pilot Kirliliğini Azaltmaya Yönelik Çağdaş Yaklaşımlar AU - Köse, Esra Cansu AU - Yayılkan, Abdulkadir AU - Kulac, Selman AU - İlk, Hakkı PY - 2022 DA - May DO - 10.31590/ejosat.1113277 JF - Avrupa Bilim ve Teknoloji Dergisi JO - EJOSAT PB - Osman SAĞDIÇ WT - DergiPark SN - 2148-2683 SP - 197 EP - 206 IS - 36 LA - en AB - Massive Multiple Input Multiple Output (MIMO) is a promising technology for meeting the demand of high data capacity for mobile networks in the future. Obtaining channel state information (CSI) in MIMO systems provides energy and spectrum efficiency. Hence, the accuracy of the CSI is very important. Time Division Duplexing (TDD) is a good alternative method to obtain CSI in Massive MIMO systems. Pilot sequences are used to obtain CSI. In practice, it is not possible to assign a different pilot sequence to each user terminal. In particular, the use of the same pilot sequences in different cells in Massive MIMO systems causes the problem of pilot contamination. Many studies have been conducted in an attempt to mitigate this problem. In this study, the reasons for pilot contamination are discussed and the methods proposed in the literature for eliminating or mitigating pilot contamination are presented. In addition, the case of pilot contamination-related security in Massive MIMO and other related issues that may be important in future systems are highlighted. KW - Pilot Contamination (PC) Mitigation KW - Massive MIMO Systems KW - Channel State Information (CSI) KW - Time Division Duplex (TDD) KW - Frequency Division Duplex (FDD). N2 - Büyük Çoklu Giriş Çoklu Çıkış (MIMO), gelecekte mobil ağlar için yüksek veri kapasitesi talebini karşılamak için umut verici bir teknolojidir. MIMO sistemlerinde kanal durum bilgisinin (CSI) elde edilmesi, enerji ve spektrum verimliliği sağlar. Bu nedenle, CSI'nin doğruluğu çok önemlidir. Zaman Bölmeli Çift Yönlendirme (TDD), Massive MIMO sistemlerinde CSI elde etmek için iyi bir alternatif yöntemdir. CSI elde etmek için pilot diziler kullanılır. Pratikte, her kullanıcı terminaline farklı bir pilot dizisi atamak mümkün değildir. Özellikle Massive MIMO sistemlerinde farklı hücrelerde aynı pilot dizilerin kullanılması pilot kontaminasyonu sorununa neden olmaktadır. Bu sorunu azaltmak için birçok çalışma yapılmıştır. Bu çalışmada, pilot kontaminasyonunun nedenleri tartışılmakta ve pilot kontaminasyonunu ortadan kaldırmak veya azaltmak için literatürde önerilen yöntemler sunulmaktadır. Ayrıca, Massive MIMO'da pilot kontaminasyonla ilgili güvenlik durumu ve gelecekteki sistemlerde önemli olabilecek diğer ilgili konular vurgulanmıştır. CR - ELIJAH, O. LEOW, C. Y. THAREK, A. NUNOO, S. ILIYA, S.Z. Mitigating Pilot Contamination in Massive MIMO System - 5G: An Overview. In: IEEE 10th Asian Control Conference (ASCC). Kota Kinabalu, 2015, pp. 1–6. ISBN 978-192210721-3. CR - ELIJAH, O. LEOW, C. Y. THAREK, A. NUNOO, S. ILIYA, S.Z. A Comprehensive Survey of Pilot Contamination in Massive MIMO-5G System. In:IEEE Communications Surveys & Tutorials. 2016, vol. 18, iss. 2, pp. 905 – 923.ISSN 1553-877X. DOI: 10.1109/COMST.2015.2504379. CR - SOYSAL, A. MIMO Systems with Non-exact CSI. In: IEEE 18th Signal Processing and Communications Applications Conference (SIU). Diyarbakir 2010, pp. 531 – 534. ISBN 978-1-4244-9671-6. DOI: 10.1109/SIU.2010.5653390. CR - SARKER, M.A.L., LEE, M.H. A fast channel estimation and the reduction of pilot contamination problem for Massive MIMO based on a diagonal Jacket matrix. IEEE 4th International Workshop on Fiber Optics in Access Network (FOAN). 2013, pp 26-30. ISSN 2378-8488. DOI: 10.1109/FOAN.2013.6648821. CR - BANDIRMALI, N. ÇEKEN, C. BAYILMIŞ, C. ERTURK, İ. Kablosuz Erişim Yöntemlerinin Karşılaştırmalı İncelenmesi. Elektrik, Elektronik, Bilgisayar Mühendisliği 11. Ulusal Kongresi EMO , İstanbul ,2005 pp 95-98. CR - BADIR, M.M., FOUDA, M.M., TAG ELDIEN, A.S. A novel vision to mitigate pilot contamination in Massive MIMO-based 5G networks. IEEE 11th International Conference on Computer Engineering & Systems (ICCES) . Cairo,2016, pp366-371. DOI: 10.1109/ICCES.2016.7822031 CR - SAXENA, V. Pilot Contamination and Mitigation Techniques in Massive MIMO Systems. LTH, 2014. PhD thesis. Department of Electrical and Information Technology Lund University. Supervisor: Dr. Eleftherios Karipidis, Dr. Gábor Fodor CR - BJÖRNSON, E., HOYDIS, J. KOUNTOURIS, M. Massive MIMO Systems With Non-Ideal Hardware: Energy Efficiency, Estimation, and Capacity Limits. IEEE Journals & Magazines, IEEE Transactions on Information Theory. 2014, vol. 60, iss.11, pp.7112-7139. ISSN: 0018-9448. DOI: 10.1109/TIT.2014.2354403. CR - ABBOUD, A. (2017). Interference Mitigation in 5G Mobile Networks Uplink Pilot Contamination in TDD Massive MIMO Scheme. France, 2017. PhD thesis, Université de Limoges.. Supervisor: Jean-Pierre Cances, Ali Jaber et Vahid Meghdadi. CR - ALQAHTANI, A.H. SULYMAN, A.I. ALSANIE, A. 2016. Rateless space–time block code for mitigating pilot contamination effects in multi-cell Massive MIMO system with lossy links. IET Journals & Magazines, IET Communications. 2016 vol .10, iss. 16, pp 2252-2259. ISSN: 1751-8636DOI: 10.1049/iet-com.2016.0283 CR - WU, L. ZHANG, Z. DANG, J. Enhanced Time-shifted Pilot based Channel Estimation in Massive MIMO Systems with Finite Number of Antennas. 2017 IEEE International Conference on Communications Workshops (ICC Workshops). Paris, 2017. pp 222-227. ISBN: 978-1-5090-1525-2.DOI:10.1109/ICCW.2017.79 62661. CR - WANG, H., YANG, L., ZHU, H. Pilot contamination reduction based on MSE performance of channel estimation. IEEE International Conference on Wireless Communications & Signal Processing (WCSP), Nanjing, 2015. pp 1-5. ISBN: 978-1-4673-7687-7 DOI: 10.1109/WCSP.2015.7341048 CR - MA, S., JIANG, S., LONG, T. Pilot contamination reduction based on improved power control in M-MIMO systems. IET Conferences, 11th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM), Shanghai 2015.pp1-6.ISBN: 978-1-78561-035-6 DOI: 10.1049 /cp . 2015.0705 CR - APPAİAH, K., ASHİKHMİN, A., MARZETTA, T.L. Pilot Contamination Reduction in Multi-User TDD Systems. IEEE Conferences, 2010 IEEE International Conference on Communications, Cape Town, 2010. pp 1-5. ISBN: 978-1-4244-6404-3.DOI: 10.1109/ICC.2010. 5502810 CR - MAHYIDDIN, W.A.W.M., MARTIN, P.A., SMITH, P.J. Pilot Contamination Reduction Using Time-Shifted Pilots in Finite Massive MIMO Systems. IEEE Conferences, 2014 IEEE 80th Vehicular Technology Conference (VTC2014-Fall). Vancouver, 2014 pp1-5. ISBN: 978-1-4799-4449 DOI: 10.1109/VTCFall.2014.6966130 CR - VU, T.X., VU, T.A., QUEK, T.Q.S. Successive Pilot Contamination Elimination in Multiantenna Multicell Networks. IEEE Journals & Magazines, IEEE Wireless Communications Letters. 2014 vol. 3, iss. 6, pp 617-620. ISSN: 2162-2345. DOI: 10.1109/LWC.2014.2361518. CR - UPADHYA, K., VOROBYOV, S.A., VEHKAPERA, M. (2016). Superimposed pilots: An alternative pilot structure to mitigate pilot contamination in Massive MIMO. IEEE Conferences, 2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). Shanghai 2016. pp 3366-3370. ISBN: 978-1-4799-9988-0 DOI: 10.1109/ICASSP.2016.7472301 CR - UPADHYA, K., VOROBAYOV, S.A., VEHKAPERA, M. Superimposed Pilots Are Superior for Mitigating Pilot Contamination in Massive MIMO. IEEE Journals & Magazines, IEEE Transactions on Signal Processing, vol. 6, iss. 11, 2017 pp 2917-2932. ISSN: 1941-0476. DOI: 10.1109/TSP.2017.2675859. CR - NEUMANN, D., JOHAM, M., UTSCHICK, W. Suppression of pilot contamination in Massive MIMO systems. IEEE Conferences, 2014 IEEE 15th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Toronto 2014 pp 11-15. ISBN: 978-1-4799-4903-8 DOI: 10.1109/SPAWC. 2014.6941307. CR - WANG, H., PAN, Z., NI, J. A spatial domain based method against pilot contamination for multi-cell Massive MIMO systems. IEEE 8th International Conference on Communications and Networking in China (CHINACOM). Guilin 2013 pp 218-222. ISBN: 978-1-4799-1406-7. DOI: 10.1109/ChinaCom.2013.6694594 CR - YIN, H., GESBERT, D., FILIPPOU, M. A Coordinated Approach to Channel Estimation in Large-Scale Multiple-Antenna Systems. IEEE Journal on Selected Areas in Communications ,vol. 31, iss. 2, 2013. pp 264-273. ISSN: 1558-0008 DOI: 10.1109/JSAC.2013.130214. CR - AHMADI, H., FARHANG, A., MARCHETTI, N. A Game Theoretic Approach for Pilot Contamination Avoidance in Massive MIMO. IEEE Journals & Magazines, Wireless Communications Letters 2016. vol. 5, iss. 1, pp 12-15. ISSN: 2162-2345 DOI: 10.1109/LWC.2015.2487261. CR - ALKHALED, M., ALSUSA, E., HAMDI, K.A. A New Allocation Algorithm for Pilot Contamination Mitigation in TDD Massive MIMO Systems. 2017 IEEE Wireless Communications and Networking Conference (WCNC). San Francisco 2017. pp 1-6. ISBN: 978-1-5090-4183-1. DOI: 10.1109/WCNC.2017.7925938. CR - LIN, S., HUANG, K., LUO, W. Analysis of Pilot Contamination on the Security Performance of Artificial Noise in MIMO Systems. 2015 IEEE 81st Vehicular Technology Conference (VTC Spring). Glasgow 2015. pp 1-5. ISBN: 978-1-4799-8088-8 DOI: 10.1109/VTCSpring.2015.7145701. CR - ZHOU, X., MAHAM, B., HJORUNGNES, A. Pilot Contamination for Active Eavesdropping. IEEE Transactions on Wireless Communications, vol. 11, iss. 3,2012 pp 903- 907. ISSN: 1558-2248 DOI: 10.1109/TWC.2012.020712.111298. CR - WANG, H. PAN, Z. NI, J. A Temporal Domain Based Method against Pilot Contamination for Multi-Cell Massive MIMO Systems. 2014 IEEE 79th Vehicular Technology Conference (VTC Spring), Seoul 2014. pp 1-5. ISBN: 978-1-4799-4482-8 DOI: 10.1109/VTCSpring.2014.7022799. CR - ALKHALED, M. ALSUSA, E. HAMDI, K.A. Adaptive Pilot Allocation Algorithm for Pilot Contamination Mitigation in TDD Massive MIMO Systems. 2017 IEEE Wireless Communications and Networking Conference (WCNC), San Francisco 2017. pp 1-6. ISBN: 978-1-5090-4183-1. DOI: 10.1109/WCNC.2017.7925885. CR - SOHN, J. Y. YOON, S.W. MOON, J. On Reusing Pilots Among Interfering Cells in Massive MIMO. IEEE Journals & Magazines, IEEE Transactions on Wireless Communications, vol. 16, iss. 12, 2017 pp 8092-8104. ISSN: 1558-2248. DOI: 10.1109/TWC.2017.2756927 CR - GOPALAKRISHNAN, B. JINDAL, N. An Analysis of Pilot Contamination on Multi-User MIMO Cellular Systems with Many Antennas. Signal Processing Advances in Wireless Communications (SPAWC), 2011 IEEE 12th International Workshop on San Francisco. 2011. pp 381-385. ISSN: 1948-3252. DOI: 10.1109/SPAWC.2011.5990435. CR - LUO, X. ZHANG, X. Flexible Pilot Contamination Mitigation with Doppler PSD Alignment. IEEE Journals & Magazines, IEEE Signal Processing Letters, 2016 vol. 23, iss.10, pp 1449-1453. ISSN: 1558-2361. DOI: 10.1109/LSP.2016.2601270 CR - WEINA YUAN., XINKAI YANG., RUI XU. A Novel Pilot Decontamination Scheme for Uplink Massive MIMO Systems. 8th International Congress of Information and Communication Technology (ICICT-2018). Procedia Computer Science 131 2018 pp 72–79. DOI: 10.1016/j.procs.2018.04.187. CR - SHUAI MA., EASTON LI XU., AMIR SALIMI., SHUGUANG CUI. A Novel Pilot Assignment Scheme in Massive MIMO Networks. IEEE Wıreless Communıcatıons Letters, 2018 Vol. 7, No. 2. pp 262-265 ISSN: 2162-2345. DOI: 10.1109/LWC.2017.2771285 CR - LIY, Y. CHENY, Y. HUANG, H. JING, X. On Massive MIMO Performance with a Pilot Assignment Approach Based on Hungarian Method. 2016 16th International Symposium on Communications and Information Technologies (ISCIT). Qingdao 2016. ISBN: 978-1-5090-4099-5. DOI: 10.1109/ISCIT.2016.7751694. CR - ZHOU, R. FU, Y. WANG H. Uplink Asynchronous Fractional Pilots Scheduling in Massive MIMO System. 2018 18th IEEE International Conference on Communication Technology. Chongqing 2018. pp 402 - 406 ISBN: 978-1-5386-7635-6. DOI: 10.1109/ICCT.2018.8600231 CR - KIM, K . LEE, J. CHOI, J. Deep Learning Based Pilot Allocation Scheme (DL-PAS) for 5G Massive MIMO System. IEEE Communications Society , 2018. vol. 22, iss.4, Pp 828 - 831. ISSN: 1558-2558 DOI: 10.1109/LCOMM.2018.2803054 CR - KOSE, E.C., KULAÇ, S. Effective Pilot Contamination Mitigation Approach with Hybrid Method in 5G and Beyond Systems. 3rd Scientific and Vocational Studies Congress BILMES 2019, NEVŞEHİR, TURKEY, 2019 CR - YAYILKAN, A., KULAÇ, S. Effective Pilot Assignment Approach with Ant Colony Optimization in Pilot Contamination Mitigation in Next Generation Mobile Communication Systems. International Symposium on Academic Studies in Science, Engineering and Architecture Sciences ISMS 2019, ANKARA, TURKEY, 2019 CR - HU. C. WANG. H. SONG. R "Pilot Decontamination in Multi-Cell Massive MIMO Systems via Combining Semi-Blind Channel Estimation With Pilot Assignment," in IEEE Access, vol. 8, pp. 152952-152962, 2020, doi: 10.1109/ACCESS.2020.3015263. CR - ZENG. W. HE.Y. LI. B. and WANG. S. "Pilot Assignment for Cell Free Massive MIMO Systems Using a Weighted Graphic Framework," in IEEE Transactions on Vehicular Technology, vol. 70, no. 6, pp. 6190-6194, June 2021, doi: 10.1109/TVT.2021.3076440. CR - NGUYEN. T. H., CHIEN T. V., NGO. H. Q., TRAN. X. N., BJÖRNSON E., "Pilot Assignment for Joint Uplink-Downlink Spectral Efficiency Enhancement in Massive MIMO Systems With Spatial Correlation," in IEEE Transactions on Vehicular Technology, vol. 70, no. 8, pp. 8292-8297, Aug. 2021, doi: 10.1109/TVT.2021.3091020. UR - https://doi.org/10.31590/ejosat.1113277 L1 - https://dergipark.org.tr/en/download/article-file/2413983 ER -