Abstract
In hybrid free space optical/radio frequency (FSO/RF) systems, switching between the optical and RF links depends on the optical and RF signal to noise ratio (SNR) threshold levels; therefore, the correct choice of these threshold levels is essential to make best use of the complementary nature of optical and RF links. Optimal selection of these threshold levels is the prime objective of this paper. A hybrid FSO/RF system using modified switching scheme with two optical and one RF threshold is considered. Here, we propose an algorithm to obtain the optimized thresholds, which yield minimum bit error rate (BER) for a given outage probability under a constraint on maximum transmitted power. The optimized thresholds are dependent on the average optical and RF SNR. Hybrid FSO/RF system use both optical as well as RF power. The average system SNR is computed by considering the actual optical and RF power consumption. Also the performance of the hybrid FSO/RF system is studied with respect to average system SNR using optimized optical and RF thresholds. This analysis reveals the existence of a critical operating point of average optical SNR, beyond which the system should be preferably operated to ensure minimum BER.
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Ghassemlooy, G., Popoola, W., Rajbhandari, S.: Optical Wireless Communications: System and Channel Modelling with MATLAB, 1st edn. CRC Press, Boca Raton (2017)
Khalighi, M.A., Uysal, M.: Survey on free space optical communication: a communication theory perspective. IEEE Commun. Surv. Tuto. 16(4), 2231–2258 (2014)
Abadi, M.M., Ghassemlooy, Z., Zvanovec, S., Bhatnagar, M.R., Wu, Y.: Hard switching in hybrid FSO/RF link: investigating data rate and link availability. In: IEEE ICC (Workshop 2017), pp. 463–468 (2017)
Tapse, H., Borah, D.: Hybrid optical/RF channels characterization and performance study using low-density parity check codes. IEEE Trans. Commun. 57(11), 3288–3297 (2009)
Rakia, T., Yang, H.C., Alouini, M.S., Gebali, F.: Outage analysis of practical FSO/RF hybrid system with adaptive combining. IEEE Commun. Lett. 19(8), 1366–1369 (2015)
Shrivastava, S.K., Sengar, S., Singh, S.P.: A new switching scheme for hybrid FSO/RF communication in the presence of strong atmospheric turbulence. Photon. Netw. Commun. 37(1), 53–62 (2019)
Mai, V.V., Pham, A.T.: Adaptive multi-rate designs for hybrid FSO/RF systems over fading channels. In: Globecom 2014 Workshop on Optical Wireless Communication, pp. 469–474 (2014)
Rakia, T., Yang, H.C., Gebali, F., Alouini, M.S.: Power adaptation based on truncated channel inversion for hybrid FSO/RF transmission with adaptive combining. IEEE Photon. J. 7(4), 1–13 (2015)
Touati, A., Abdaoui, A., Touati, F., Uysal, M., Bouallegue, A.: On the effects of combined atmospheric fading and misalignment on the hybrid FSO/RF transmission. J. Opt. Commun. Netw. 8(10), 715–725 (2016)
Nath, S., Shrivastava, S.K., Sengar, S., Singh, S.P.: Novel architectures for efficient RF usage in hybrid FSO/RF system. In: IEEE International Conference on Advanced Networks and Telecommunications Systems (ANTS), pp. 1–6 (2018).
Bag, B., Das, A., Ansari, I.S., Prokes, A., Bose, C., Chandra, A.: Performance analysis of hybrid FSO systems using FSO/RF-FSO link adaptation. IEEE Photon. J. 10(3), 1–17 (2018)
Andrews, L.C., Phillips, R.L.: Laser Beam Propagation Through Random Media, 2nd edn. SPIE Press, Bellingham (2005)
Kaushal, H., Jain, V.K., Kar, S.: Free Space Optical Communication, Optical Networks Series. Springer, New Delhi (2017)
Djordjevic, G.T., Petkovic, M.I., Spasic, M., Antic, D.S.: Outage capacity of FSO link with pointing errors and link blockage. Opt. Express 24(1), 219–230 (2016)
Popoola, W.O., Ghassemlooy, Z.: BPSK subcarrier intensity modulated free-space optical communications in atmospheric turbulence. J. Lightw. Technol. 27(8), 967–973 (2009)
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We would like to thanks the Department of ECE, NSIT, New Delhi, INDIA for providing us necessary tools and facilities for the research.
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Shrivastava, S.K., Sengar, S., Singh, S.P. et al. Threshold optimization for modified switching scheme of hybrid FSO/RF system in the presence of strong atmospheric turbulence. Photon Netw Commun 40, 103–113 (2020). https://doi.org/10.1007/s11107-020-00901-z
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DOI: https://doi.org/10.1007/s11107-020-00901-z