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27.P.Varzakas, "Estimation of optimum antennas number of a spread spectrum MIMO system under signal fading”, WSEAS Transactions on Computers, Volume 18, pp. 281-284, 2019.
26. P.Varzakas, "On the Radio Capacity of a Spread Spectrum Cognitive Radio System”, WSEAS Transactions on Communications, Volume 18, pp. 179-184, 2019.
25.P.Varzakas, "On the Optimum Power Allocation in a Cellular DS/FFH-CDMA System”, WSEAS Transactions on Communications, Volume 14, pp. 50-53, 2015.
24. P.Varzakas, "On the Optimum Power Allocation in a Cellular DS/FFH-CDMA System”, WSEAS Transactions on Communications, Volume 14, pp. 50-53, 2015.
23. P.Varzakas, "On the Statistics of the Channel Capacity for a DS/FFH-CDMA System”, WSEAS Transactions on Communications, vol.13,pp.494-499, 2014.
22.P.Varzakas, "Spectral Efficiency Comparison of TDMA and DS-CDMA in Cellular Mobile Radio Systems”, WSEAS Transactions on Communications, vol. 13, pp. 195-200, 2014.
21.P.Varzakas, "MC/DS-CDMA Versus SC/DS-CDMA in Mobile Radio: Spectral Efficiency Approach", WSEAS Transactions on Communications, Issue 6, Volume 12, pp. 241-250,June 2013.
20. P.Varzakas, "Optimum processing gain for a hybrid direct sequence/slow frequency hopping code division multiple access cellular system over Rayleigh fading channels: the direct sequence/slow frequency hopping code division multiple access case", International Journal of Communication Systems (John Wiley & Sons, Ltd.), vol. 25, no.8, pp.1034-1043, Aug.2012.
19. P.Varzakas, "Channel Capacity per user in a Power and Rate Adaptive Hybrid DS/FFH-CDMA Cellular System over Rayleigh Fading Channels", International Journal of Communication Systems (John Wiley & Sons, Ltd.), vol. 25, no.7, pp.943-952, July 2012.
18. P.Varzakas, “On the Optimum Processing Gain for a Hybrid DS/FFH-CDMA Cellular System over Rayleigh Fading Channels", International Journal of Communication Systems (John Wiley & Sons, Ltd.), vol.24, no.7, July 2011, pp.902-910.
17. P.Varzakas, “Radio Capacity Estimation of single-cell Spread Spectrum MIMO and Adaptive Rate DS/FFH-CDMA Systems under Rayleigh Fading Conditions”, The Mediterranean Journal of Electronics and Communications (Soft Motor Ltd, UK), vol. 6, no.4, 2010, pp.113-119 (ISSN: 1744-2400).
16. P.Varzakas, “Optimal distance Estimation in Cellular DS/SFH-CDMA System under Rayleigh Fading”, The Mediterranean Journal of Electronics and Communications (Soft Motor Ltd, UK), vol. 5, no.1, 2009, pp.13-17 (ISSN: 1744-2400).
15. P.Varzakas, “Optimal SIR for an hybrid cellular DS/SFH-CDMA system”, International Journal of Communication Systems (John Wiley & Sons, Ltd.), vol. 21, no.5, May 2008. pp. 549-557.
14. P.Varzakas, “Information-Theoretic Comparison of Fading Channel Capacity for FDMA and DS-CDMA in a Rayleigh Fading Environment”, WSEAS Transactions on Communications, Issue 2, vol. 7, Feb. 2008. pp. 52-57.
13. P.Varzakas, “Optimization of an OFDM Rayleigh fading system”, International Journal of Communication Systems (John Wiley & Sons, Ltd.), vol. 20, no.1, Jan. 2007, pp. 1-7 (paper in the top of download charts from the International Journal of Communication Systems in 2007, Wiley).
12. P.Varzakas, “Average Channel Capacity for Rayleigh Fading Spread Spectrum MIMO systems”, International Journal of Communication Systems, vol. 19, no.10, Dec.2006, pp. 1081-1087.
11. P.Varzakas and G.S.Tombras, “Spectral Efficiency of a Single Cell Multi-Carrier DS-CDMA System in Rayleigh Fading”, Journal of the Franklin Institute-Engineering and Applied Mathematics, vol. 343, no.3, May 2006, pp. 295-300.
10. P.Varzakas and G.S.Tombras, “Spectral efficiency of a cellular MC/DS-CDMA system in Rayleigh fading”, International Journal of Communication Systems, (John Wiley & Sons, Ltd.), vol. 18, no.8, Oct. 2005, pp. 795-801.
9. N.C.Sagias, P.Varzakas, G.S.Tombras and G.K.Karagiannidis, “Spectral Efficiency for Selection Combining RAKE receivers over Weibull Fading Channels”, Journal of the Franklin Institute-Engineering and Applied Mathematics, vol. 342, no.1, Jan 2005, pp. 7-13.
8. P.Varzakas, “Optimal Radio Capacity for an Hybrid DS/SFH CDMA System in Cellular Radio”, IEE Electronics Letters, vol.40, no. 7, April 2004, 440-441.
7. N.C.Sagias, P.Varzakas, G.S.Tombras and G.K.Karagiannidis, “Average channel capacity for Generalized-Selection Combining RAKE Receivers”, European Transactions on Telecommunications, vol. 15, no.5, Sept./Oct. 2004, pp. 497-500.
6. P.Varzakas and G.S.Tombras, “Optimal Hop number of an adaptive hybrid DS/FFH CDMA in Rayleigh fading”, IEE Electronics Letters, vol.39, no.6, March 2003, pp. 557-558.
5. P.Varzakas and G.S.Tombras, “Spectral efficiency of adaptive hybrid DS/FFH CDMA in Rayleigh fading”, IEE Electronics Letters, vol. 39, no.1, Jan. 2003, pp. 145-147.
4. P.Varzakas and G.S.Tombras,“Average channel capacity for RAKE receivers”, IEE Electronics Letters, vol. 38, no.10, May 2002, pp. 475-476.
3. P.Varzakas and G.S.Tombras,“Spectral efficiency for a hybrid DS/FH CDMA system in cellular mobile radio”, IEEE Transactions on Vehicular Technology, vol.50, Nov. 2001, pp. 1321-1327.
2. P.Varzakas and G.S.Tombras, “Spectral Efficiency of Direct-Sequence Code Division Multiple Access in Cellular Mobile Radio”, International Journal of Communication Systems (John Wiley & Sons, Ltd.), 10, 1997, pp. 247-252.
1. P.Varzakas and G.S.Tombras,“Comparative Estimate of User Capacity for FDMA and Direct-Sequence CDMA in Mobile Radio”, International Journal of Electronics, vol. 83, no.1, July 1997, pp. 133-144.
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20.P.Varzakas, “Statistics of the Channel Capacity in a Cellular DS/FFH-CDMA Rayleigh Fading System”, Proceedings of the 2013, International Conference on Electronics and Communication Systems (ECS 2013), pp. 131-135, Rhodes Island, Greece, July 16?19, 2013.
19. P.Varzakas, “Optimizing Power Allocation in a CellularDS/FFH-CDMA System under Rayleigh Fading, Proceedings of the 2013 International Conference on Electronics and Communication Systems (ECS 2013), pp. 127-130, Rhodes Island, Greece, July 16?19, 2013.
18. P.Varzakas, “Estimation of Radio Capacity of a Spread Spectrum Cognitive Radio Rayleigh Fading System”, ACM Proceedings of the 17th Pan-Hellenic Conference on Informatics with International Participation (PCI 2013), pp.63-66, Sept. 19-21, 2013, Thessaloniki, Greece.
17. P.Varzakas, “Analytical Mathematical Expression for the Channel Capacity of a Power and Rate Simultaneous Adaptive Cellular DS/FFH-CDMA System in a Rayleigh Fading Channel“, Proceedings of the 2010 International Conference on Communication and Information Technologies (ICCIT 2010), Paris, France, 28-30 July 2010, pp. 1323-1326, Issue 67 (ISSN 2070-3724) pp. 1323-1326.
16. P.Varzakas, “Optimum Radio Capacity Estimation of a Single-Cell Spread Spectrum MIMO System under Rayleigh Fading Conditions”, Proceedings of the 2009 International Conference on Communications Systems and Technologies (ICCST’'09), Oslo, Norway, 29-31 July 2009, pp. 212-215.
15. P.Varzakas, “Closed-form expression for the optimum antennas number of a spread spectrum MIMO system under rayleigh fading conditions”, Proceedings of the 13th WSEAS International Conference on Communications, Rodos, Greece, 23-25 July 2009, pp. 56-59.
14. P.Varzakas, “Optimal radio capacity of a rayleigh fading single-cell spread spectrum MIMO system, 2008 International Conference on Telecommunications, (ICT 2008), St. Petersburg, 16-19 June 2008, pp.1-5.
13. P.Varzakas, “Optimizing Processing Gain of a Cellular DS/FFH-CDMA Rayleigh Fading System”, Proceedings of the 10th IEEE International Symposium on Spread Spectrum Techniques and Applications (ISSSTA) 2008, Creating New Dimensions in the Wireless World, Bologna, Italy, 25-28 August 2008, pp.523-527.
12. P.Varzakas, “Average Channel Capacity for a Power and Rate Adaptive DS/FFH CDMA Cellular System”, Proceedings of the Fifth International Symposium on Communications Systems, Netwroks and Digital Signal Processing (CSNDSP 2006), Greece, Patra, 2006, pp.92-95.
11. P.Varzakas, “Optimal distance estimation for the Spectral Efficiency of an Hybrid Cellular DS/SFH CDMA System”, Proceedings of the 38th IEEE International Symposium on Circuits and Systems (???? ISCAS 2006), Greece, Kos, 2006, pp.1359-1361.
10. P.Varzakas, “Optimal radio capacity for an adaptive Hybrid DS/FFH-CDMA system in Rayleigh fading”, Proceedings of the First IEEE International Symposium on New Frontiers in Dynamic Spectrum Access (IEEE DYSPAN 2005), USA, Batimore, 2005, pp. 642-644.
9. P.Varzakas and G.S.Tombras, “Spectral efficiency for an adaptive hybrid DS/FFH-CDMA system in a Rayleigh fading channel”, Proceedings of the 5th European Workshop on Mobile/Personal Satcoms (EMPS 2002), Baveno-Stresa, Lake Maggiore, Italy, Sept.2002, pp.139-145.
8. P.Varzakas and G.S.Tombras, “Comparative estimation of FDMA and CDMA channel capacity in a Rayleigh fading channel”, Proceedings of the International Symposium on 3rd Generation Infrastructure and Services (3GIS), Athens, Greece, 2-3 July 2001, pp. 139-143.
7. P.Varzakas and G.S.Tombras, “Estimation of spectral efficiency for MC/DS-CDMA in cellular systems”,Proceedings of the Communications Symposium 2000 IEEE Benelux Chapter on Vehicular Technology and Communications (IEEE-SVTC), IMEC, Leuven, Belgium, Oct. 2000, pp. 60-66.
6. P.Varzakas and G.S.Tombras, “Spectral efficiency for TDMA and Direct-Sequence CDMA in cellular systems”, Proceedings of the 7th International Conference on Advances in Communications and Control: TELECOMMUNICATIONS / SIGNAL PROCESSING (COMCON 7), Athens, Greece, June-July 1999, pp. 613-620.
5. D.E.Ventzas, P.Tsitsipis, K.Kalovrektis and P.Varzakas, “Microcontroller Control for an Electro-pneumatic Manipulator”, Proceedings of the EURICSON’98, SIRES/IEEE/CSS Third European Robotics, Intelligent Systems & Control Conference-SOFTCOM’98 IMACS/IFAC International Symposium on Soft Computing in Engineering Applications, June 1998, pp. 98.
4. P.Varzakas and G.S.Tombras, “Spectral efficiency for FDMA and DS-CDMA in cellular systems”, Proceedings of the 9th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, (PIMRC’98), USA, Boston, Sept.,1998, pp. 1121-1125.
3. P.Varzakas and G.S.Tombras, “Estimation of spectral efficiency for hybrid DS/FH CDMA in cellular mobile radio”, Proceedings of the International Conference on Telecommunications (ICT’98), Greece, 1998, pp.22-26.
2. P.Varzakas and G.S.Tombras, “Spectral efficiency for FDMA and Direct-Sequence CDMA in mobile radio”, Proceedings of the 6th International Conference on Advances in Communications and Control: TELECOMMUNICATIONS/ SIGNAL PROCESSING (COMCON 6), Greece, 1997, pp.847-853.
1. P.Varzakas and G.S.Tombras, “Estimation of Spectral Efficiency of Direct-Sequence Code Division Multiple Access in Cellular Mobile Radio”, Proceedings of the International Workshop on Mobile Communications, (IWMC’96), Greece, Thesaloniki, Sept. 1996, pp.184-188.