Huan Yu Yunzhou Li Marios Kountouris Xibin Xu Jing Wang 0001 Energy efficiency analysis of relay-assisted cellular networks using stochastic geometry. 667-671 2014 WiOpt https://dl.ifip.org/db/conf/wiopt/wiopt2014/YuLKX014.pdf https://doi.org/10.1109/WIOPT.2014.6850363 conf/wiopt/2014 db/conf/wiopt/wiopt2014.html#YuLKX014