[1] [1] M. T. Dabiri and S. M. S. Sadough, IEEE Communications Letters 21, 2170 (2017).

[2] [2] J. Libich, J. Perez, S. Zvanovec, Z. Ghassemlooy, R. Nebulo-ni and C. Capsoni, Applied Optics 56, 336 (2017).

[3] [3] K. Wang, A. Nirmalathas, C. Lim, K. Alameh and E. Skafi-das, Journal of Optical Communications and Networking 9, A189 (2017).

[4] [4] X. Liu, P. Wang and T. Cao, Optoelectronics Letters 12, 366 (2016).

[5] [5] H. Fu, P. Wang, R. Wang, X. Liu, L. Guo and Y. Yang, Optoe-lectronics Letters 12, 294 (2016).

[6] [6] R. Barrios and F. Dios, Optics Express 20, 13055 (2012).

[7] [7] R. Barrios and F. Dios, Optics Laser Technology 45, 13 (2013).

[8] [8] P. Wang, N. Xiang, Q. Gao, R. Wang, L. Guo and Y. Yang, IEEE Photonics Journal 8, 7902415 (2016).

[9] [9] J. Abouei and K. N. Plataniotis, Journal of Lightwave Tech-nology 30, 1351 (2012).

[10] [10] I. B. Djordjevic, Journal of Optical Communications and Networking 2, 221 (2010).

[11] [11] A. Eslami, S. Vangala and H. Pishro-Nik, IEEE Transactions on Communications 58, 2926 (2010).

[12] [12] I. S. Gradshteyn and I. M. Ryzhik, Table of Integrals, Series and Products, Amsterdam, The Netherlands: Elsevier, 2007.

[13] [13] D. Gesbert and M.-S. Alouini, How Much Feedback is Multi-User Diversity Really Worth IEEE International Conference on Communications, 234 (2004).

[14] [14] P. Viswanath, D. N. C. Tse and R. Laroia, IEEE International Symposium on Information Theory 48, 1277 (2002).

[15] [15] M. O. Sunay and A. Eksim, Wireless Multicast with Multi-User Diversity, IEEE Vehicular Technology Conference, 1584 (2004).