[IEEE 2012 9th International Symposium on Wireless Communication Systems (ISWCS 2012) - Paris, France (2012.08.28-2012.08.31)] 2012 International Symposium on Wireless Communication Systems (ISWCS) - Energy saving in the optimization of the planning of fixed WiMAX with relays in hilly terrains: Impact of sleep modes and cell zoomingVelez, Fernando J.; Oliveira, Joao; Robalo, Daniel; Holland, Oliver; Aghvami, A. Hamid · 2012