DEVELOPMENT OF A DATA RATE-BASED SLEEP MODE ALGORITHM FOR ENERGY SAVINGS IN AN LTE HETEROGENEOUS NETWORK FOR A PICO eNodeB CELL

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Department of Engineering

ABSTRACT
There are several energy saving algorithms proposed to save energy in heterogeneous networks, but most of these algorithms achieved energy savings at the expense of service provisioning. Base stations significantly contribute to power consumption in cellular networks. This research work presented a Data Rate-Based Sleep Mode Algorithm for energy savings for a pico evolved NodeB (eNodeB) cell in aLong Term Evolution (LTE) heterogeneous network (HetNet). The algorithm was able to track traffic situations and estimate user data rate and energy consumption in the heterogeneous network. The algorithm switched the operating state of some pico eNodeB cells to sleep mode (inactive state) at low (less than or equal to 10 user equipment per macro area coverage)and medium traffic (greater than 10 user equipment per macro area coverage) during which the users are offloaded to other pico eNodeB and macro eNodeB cells to save overall energy consumption in the network. As traffic increased (greater than 10) and the average user data rate of the overall network reduced (less than 2Mbps), the pico eNodeB cells woke up (active state) to ensure service delivery was not obstructed. The work considers temporal fluctuations of traffic with a view to achieving higher energy savings. The traffic model, data rate model, and a powerconsumption modelare developed to implement the sleep mode algorithm. The developed sleep mode algorithm is implemented in Matrix Laboratory (MATLAB) R2013a. The developed algorithm was compared with the relevant specification of the 3rdGeneration Partnership Project (3GPP) Always-on scheme. The results showthat the developed sleep mode algorithm achieved an improvement of up to 75% and 50% in terms of energy savings for the pico eNodeB cells at low and medium traffic, respectively. For the overall HetNet, the improvements of 9.28% and 6.19% were achieved for low and medium traffic, respectively. The improvements of 9.45% and 6.30% are achieved in terms of the energy efficiency in 3GPP HetNet Configuration 4b for low and medium traffic while the improvement of 9.45% and 6.22% are achieved in 3GPP HetNet Configuration 1while guaranteeing a good service delivery.