A Novel Double Modulation Technique with High Spectrum Efficiency for TDCS
The modulation techniques in traditional transform domain communication system (TDCS) exist some drawbacks, such as low transmission rate and low spectrum efficiency. We propose a novel double modulation technique with high spectrum efficiency for TDCS in this paper. First, we divide the basis function averagely into several orthogonal modules, and conduct the CSK modulation. Then, the double modulation signal waveform can be obtained by employing bipolar modulation for different module combination. Furthermore, we propose two demodulation schemes for the proposed modulation technique, namely the cyclic shift keying (CSK)-bipolar and bipolar-CSK demodulation. We also derive the mathematical expressions of their bit error rate (BER) performance. Simulation results show that for different signal-to-noise ratio (SNR), the two demodulation schemes can both achieve reliable performance, satisfactory anti-interference capabilities and effectively improve spectrum efficiency. In addition, it can be verified that CSK-bipolar demodulation can achieve the same BER with less SNR compared with bipolar-CSK demodulation.
KeywordsTDCS CSK Bipolar modulation Demodulation Spectrum efficiency
This work was supported in part by the Aeronautical Science Foundation of China under Grant 20161996010.
- 2.Sharma, M., Gupta, R.: Comparative analysis of various communication systems for intelligent sensing of spectrum. In: Proceedings of the IEEE International Conference on Advances in Computing, Communications and Informatics (ICACCI), pp. 902–908 (2014)Google Scholar
- 4.Sun, H.X., Cao, F.C., Qin, H.W.: Multiple access applications of transform domain communication system based on phase coding. In: Proceedings of the 5th IEEE International Conference on Big Data and Cloud Computing (BDCloud), pp. 217–222 (2015)Google Scholar
- 5.Sharma, M., Gupta, R.: Basis function and PN phase generation in TDCS and WDCS towards dynamic spectrum access. In: Proceedings of the 5th IEEE International Conference on Communication Systems and Network Technologies (CSNT), pp. 364–368 (2015)Google Scholar
- 8.Wu, G., Hu, S.S., Li, S.Q.: Low complexity time-frequency synchronization for transform domain communications systems. In: Proceedings of the IEEE China Summit and International Conference on Signal and Information Processing (ChinaSIP), pp. 1002–1006 (2015)Google Scholar
- 11.Charge, P., Zoubir, A., Fournier-Prunaret, D.: Enhancing spectral efficiency of transform domain communication systems by using a multidimensional modulation. In: Proceedings of the IEEE Conference on Cognitive Radio Oriented Wireless Networks and Communications (CROWNCOM), pp. 131–135 (2011)Google Scholar
- 14.Proakis, J.G., Salehi, M.: Digital Communications, 5th edn. McGraw-Hill, New York (2008). http://www.springer.com/lncs. Accessed 21 Nov 2016