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For a high speed mobile communication system, Doppler shift affects its performance seriously. In the future, broad band communication based on orthogonal frequency division multiplexing which depends on the orthogonality among sub-carriers will become popular. The absence of the orthogonality due to being destroyed by Doppler shift, leads to the failure of signal demodulation. So Doppler shift must be estimated and compensated for, which is the main purpose of previous work. On the other hand, many applications have shown that Doppler shift can be utilized to acquire the direction and speed or improve the quality of a signal. In this paper, we propose a method of not only estimating and compensating for Doppler shift, but also generating multiple non-frequency shifted signals, which can be regarded as the output of a virtual antenna array. As to the method, uniform phase sampling is the key algorithm. At first, the relation between uniform time sampling and uniform phase sampling is discussed in detail. This relation shows that the equivalence between uniform phase sampling and uniform time sampling is the necessary and sufficient condition for a non Doppler shifted signal. Next, the algorithm of Doppler shift compensation and virtualized antenna array is proposed, in which 1) original Doppler shifted signal is processed with interpolation, 2) new signals are generated by uniform phase sampling and buffered, 3) buffered new signals are read out by uniform time sampling. The theory of this process and the performance improvement for a high speed mobile communications system is mathematically analyzed, and the hardware architecture model of this algorithm is also given. The diversity gain could be obtained when an antenna array is used. In order to verify that this virtualized antenna array has the same benefit, the ability to suppress the interference and the bit error rate is analyzed with numerical simulation. The number of virtual elements and the virtual element distance are two variables related to the direction pattern of virtual antenna array. The effects of these two variables are given by the simulation, showing that the more virtual elements, the narrower beam are obtained. But more virtual elements result in more complicated hardware source. In addition, the communications scenarios of two communications radiators at different sites are simulated to verify whether this algorithm can suppress interference signal. The frequency spectrum of beamformed virtual antenna array signal shows that the interference signal can be suppressed effectively. These characteristics cannot be provided by pure Doppler frequency shift compensation. Thus these results show that high speed mobile communication systems on aircrafts or high speed trains would obtain better performances when a received Doppler shift signal is processed by this method to construct a virtual antenna array.
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Keywords:
- mobile communications /
- signal processing /
- antenna array /
- Doppler shift
[1] Nyongesa F, Djouani K, Olwal T, and Hamam Y 2015 Mobi. Inform. Sys. 2015 438159
[2] Feukeu E A, Djouani K, Kurien A 2015 Proceedings of the 6th International Conference on Ambient Systems, Networks and Technologies London, United Kingdom, June 2-5, 2015 p51
[3] Etienne A F, Karim D, Anish K 2014 Smart Comput. Rev. 4 435
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[7] Zhao R C, Xia H Y, Dou X K, Sun D S, Han Y L, Shangguan M J, Guo J, Shu Z F 2015 Chin. Phys. B 24 024218
[8] Ye Y X, Xuan Z Q, Gu J S, Xuan Y 2014 Chin. Phys. B 23 120601
[9] Baharak S, Ali M D, Ali S, Markku R 2014 EURA. J. Adv. Sig. Process. 2014 143
[10] Yang D G, Luo Y G, Li B, Li K Q, Lian X M 2010 Acta Phys. Sin. 59 4738 (in Chinese) [杨殿阁, 罗禹贡, 李兵, 李克强, 连小珉 2010 物理学报 59 4738]
[11] Li B, Zhou S, Stojanovic M, Freitag L, Willett P 2008 IEEE J. Ocean Eng. 33 198
[12] Abdelkareem A E,Sharif B S,Tsimenidis C C, Neasham J A 2012 J. Electr. Computer Eng. 2012 139416
[13] Mason S, Berger C, Zhou S, Willett P 2008 IEEE J. Selected Areas Commun. 26 1638
[14] Zakharov Y, Morozov A 2012 Proceedings of the ECUA 11th European Conference on Underwater Acoustics Edinburgh, United Kingdom, June 2-6, 2012 p070030
[15] Zhang Y S, Zhang J P, Li X, Wu Z S 2014 Chin. Phys. B 23 108402
[16] Shangguan M J, X H Y, Dou X K, et al. 2015 Chin. Phys. B 24 094212
[17] Guo B F, Wang J L, Gao M G, et al. 2015 Chin. Phys. B 24 048402
[18] Steven P N 1997 Ph. D. Dissertation (Blacksburg: Virginia Polytechnic Institute and State University)
[19] Kamel A M, Borio D, Nielsen J, Lachapelle G 2011 Proceedings of the 2011 International Technical Meeting of the Institute of NavigationSan Diego, USA,January 24-26, 2011 p374
[20] Lian P, Lachapelle G, Ma C L 2005 Improving Tracking Performance of PLL in High Dynamics Applications San Diego, USA, January 24-26, 2005 p24
[21] Huan H, Tao X R, Tao R, Cheng X K, Dong Z, Li P F, Wang Z J, Li Y, Huang H N 2014 J. Electron. Inform. Technol. 36 577 (in Chinese) [郇浩, 陶选如, 陶然, 程小康, 董朝, 李鹏飞, 王志杰, 李宇, 黄海宁 2014 电子与信息学报 36 577]
[22] Zhang W, Wang J, Wei S L 2013 Signal Processing 93 804
[23] Li J, Stoica P, Wang Z S 2003 IEEE Trans. Sig. Process. 51 1702
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[1] Nyongesa F, Djouani K, Olwal T, and Hamam Y 2015 Mobi. Inform. Sys. 2015 438159
[2] Feukeu E A, Djouani K, Kurien A 2015 Proceedings of the 6th International Conference on Ambient Systems, Networks and Technologies London, United Kingdom, June 2-5, 2015 p51
[3] Etienne A F, Karim D, Anish K 2014 Smart Comput. Rev. 4 435
[4] Sharif B S, Neasham J, Hinton O R, Adams A E 2000 IEEE J. Ocean Eng. 25 52
[5] Zhou J, Wang Y L, Hisakazu K 2014 Acta Phys. Sin. 63 240507 (in Chinese) [周杰, 王亚林, 菊池久和 2014 物理学报 63 240507]
[6] Jiang H, Zhou J, Hisakazu K, Shao G F 2014 Acta Phys. Sin. 63 048702 (in Chinese) [江浩, 周杰, 菊池久和, 邵根富 2014 物理学报 63 048702]
[7] Zhao R C, Xia H Y, Dou X K, Sun D S, Han Y L, Shangguan M J, Guo J, Shu Z F 2015 Chin. Phys. B 24 024218
[8] Ye Y X, Xuan Z Q, Gu J S, Xuan Y 2014 Chin. Phys. B 23 120601
[9] Baharak S, Ali M D, Ali S, Markku R 2014 EURA. J. Adv. Sig. Process. 2014 143
[10] Yang D G, Luo Y G, Li B, Li K Q, Lian X M 2010 Acta Phys. Sin. 59 4738 (in Chinese) [杨殿阁, 罗禹贡, 李兵, 李克强, 连小珉 2010 物理学报 59 4738]
[11] Li B, Zhou S, Stojanovic M, Freitag L, Willett P 2008 IEEE J. Ocean Eng. 33 198
[12] Abdelkareem A E,Sharif B S,Tsimenidis C C, Neasham J A 2012 J. Electr. Computer Eng. 2012 139416
[13] Mason S, Berger C, Zhou S, Willett P 2008 IEEE J. Selected Areas Commun. 26 1638
[14] Zakharov Y, Morozov A 2012 Proceedings of the ECUA 11th European Conference on Underwater Acoustics Edinburgh, United Kingdom, June 2-6, 2012 p070030
[15] Zhang Y S, Zhang J P, Li X, Wu Z S 2014 Chin. Phys. B 23 108402
[16] Shangguan M J, X H Y, Dou X K, et al. 2015 Chin. Phys. B 24 094212
[17] Guo B F, Wang J L, Gao M G, et al. 2015 Chin. Phys. B 24 048402
[18] Steven P N 1997 Ph. D. Dissertation (Blacksburg: Virginia Polytechnic Institute and State University)
[19] Kamel A M, Borio D, Nielsen J, Lachapelle G 2011 Proceedings of the 2011 International Technical Meeting of the Institute of NavigationSan Diego, USA,January 24-26, 2011 p374
[20] Lian P, Lachapelle G, Ma C L 2005 Improving Tracking Performance of PLL in High Dynamics Applications San Diego, USA, January 24-26, 2005 p24
[21] Huan H, Tao X R, Tao R, Cheng X K, Dong Z, Li P F, Wang Z J, Li Y, Huang H N 2014 J. Electron. Inform. Technol. 36 577 (in Chinese) [郇浩, 陶选如, 陶然, 程小康, 董朝, 李鹏飞, 王志杰, 李宇, 黄海宁 2014 电子与信息学报 36 577]
[22] Zhang W, Wang J, Wei S L 2013 Signal Processing 93 804
[23] Li J, Stoica P, Wang Z S 2003 IEEE Trans. Sig. Process. 51 1702
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