1. 3GPP R2–094851. Number of antennas change, 2009. Available: http://www.3gpp.org/ftp/tsg_ran/WG2_RL2/TSGR2_67/docs/R2-094851.zip .
2. 3GPP R2–101213. Energy saving techniques for LTE, 2010. Available: http://www.3gpp.org/ftp/tsg_ran/WG2_RL2/TSGR2_69/docs/R2-101213.zip .
3. 3GPP R3–100162. Overview to LTE energy saving solutions to cell switch off/on, 2010. Available: http://www.3gpp.org/ftp/tsg_ran/WG3_Iu/TSGR3_66bis/docs/R3-100162.zip .
4. Abdulkafi, A. A., Kiong, T. S., Koh, J., Chieng, D., & Ting, A. (2012). Energy efficiency of heterogeneous cellular networks: A review. Journal of Applied Sciences (Faisalabad), 12(14), 1418–1431.
5. Abdulkafi, A. A., Kiong, T. S., Koh, J., Chieng, D., Ting, A., & Ghaleb, A. M. Energy efficiency of LTE macro base station. In Proceedings of 2012 international symposium on telecommunication technologies (ISTT) (pp. 259–264).