Switching off low utilization base stations via store carry and forward relaying

Recent research studies on green cellular networking indicate that most of the traffic is serviced by a few cell sites while the rest of the cells remain under-utilized, contributing to significant energy consumption levels. Previous proposals suggest turning off Base Stations (BSs) during low utilization periods to save energy by allowing neighboring cells to increase their coverage to provide the necessary connectivity. In this paper, an alternative (and also complimentary) method is proposed, based on the store-carry and forward (SCF) relaying paradigm that allows BSs with low utilization levels to be switched-off. The proposed SCF relaying scheme exploits the mobility of relay nodes to migrate traffic from BSs of very low utilization to neighbour BSs, allowing in that respect these sites to be switched off. To this end, a joint routing and scheduling problem is formulated to maximize the number of cell sites that can be switched off by also taking into account the communication cost of operating the network. Numerical investigations reveal that significant energy gains can be attained using the proposed SCF relaying scheme for switching off BSs.