Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
Results from the smart-phones' ubiquitous Internet access and diverse multimedia applications, there has been an explosion in mobile data communication, this incredible increase will necessitate continual high energy consumption and leads to more CO2 emissions. It is crucial to develop more energy-efficient systems because of the potential harmful effects to the environment caused by CO2 emissions. It is also significant for the cellular network operators, since the electricity bills are a considerable portion of their Operational Expenditure (OPEX).
The power consumption at base stations accounts around 60-80% of the total power consumption in a cellular network [1, 2]. Potential energy savings can be expected by implementing BSs sleeping mode, according to the traffic demands and user activity factors.
There are many performance trade-offs in optimizing BSs sleeping modes . One of them is the trade-off between service delay and power consumption of cellular networks. In this thesis, the service delay is considered as a measure of Quality of Service (QoS) user experiences.
Based on the conception of cell wilting and dynamic base stations switching, BS sleep switching algorithms are developed while the QoS of User Equipments (UEs) is guaranteed in the meantime. The switching algorithms are decentralized which means no central controller is needed. The BSs can make the switching decisions based on the feedback from UEs and its neighboring BSs. Furthermore, the implementation of the proposed algorithms is also comprehensively described at the protocol level.
An urban micro BSs network is built and used as the simulation scenario. Simulations are done with the help of the rudimentary network emulator (RUNE), a network simulator tool developed by Ericsson in MATLAB environment.
Simulation results show that up to 62% of power consumption can be saved by implementing the QoS guaranteed BS switching algorithms. Furthermore, comparisons show that the QoS guaranteed BS switching algorithms have higher performance in terms of power consumption savings and QoS to the transitional BS switching algorithms.
Many factors inuence the performance of BS switching algorithms. The analysis of the performance is challenging because the required parameters for analysis are dynamically changing during the switching processes. In this thesis, we develop a rough analysis, which gives an insight into some key factors affecting the performance.
It shows that high system traffic load results in high power consumption and poor system performance. Either a very small or very large cell radius also leads to high power consumption and poor system performance for different reasons. In addition, choosing different values of the switching threshold affects the system performance in different ways.
2014. , 69 p.