Life is short. The impact of power states on base station lifetime

We study the impact of power state transitions on the lifetime of base stations (BSs) in mobile networks. In particular, we propose a model to estimate the lifetime decrease/increase as a consequence of the application of power state changes. The model takes into account both hardware (HW) parameters, which depend on the materials used to build the device, and power state parameters, that instead depend on how and when power state transitions take place. More in depth, we consider the impact of different power states when a BS is active, and one sleep mode state when a BS is powered off. When a BS reduces the power consumption, its lifetime tends to increase. However, when a BS changes the power state, its lifetime tends to be decreased. Thus, there is a tradeoff between these two effects. Our results, obtained over universal mobile telecommunication system (UMTS) and long term evolution (LTE) case studies, indicate the need of a careful management of the power state transitions in order to not deteriorate the BS lifetime, and consequently to not increase the associated reparation/replacement costs

이동 셀이 포함된 이종 셀룰러 네트워크에서 자원할당에 관한 연구

학위논문 (석사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 8. 이용환.Due to the popularity of smart phones and wireless services, demand for high traffic has become a heavy burden in wireless cellular communication system. Deployment of small cells has been proposed as one of feasible solutions to support increasing traffic demand. However, it may need to resolve technical issues including the management of frequent handovers, cross-tier and inter-cell interference. In this thesis, we consider the employment of small moving cells (SMCs) in a heterogeneous cellular network to improve transmission performance of the whole network. An SMC can provide services for a small number of users moving together with a mobility of up to a few hundred Km/hour. For ease of interference management and in consideration of SMC mobility, the macro cell shares the resource with SMCs in an orthogonal manner. To maximally utilize the resource, the macro cell adjusts the amount of resource for the SMCs in response to the change of SMC operational environments and utilizes the rest of the resource for itself. It can also allocate resource to each SMC in an orthogonal manner. Exploiting that the peak-to-average load ratio (PALR) is much larger than one, SMCs can maximally utilize the resource without inter-cell interference. Finally, the proposed resource allocation scheme is verified by computer simulation.Contents Abstract i Contents iii List of Figures iv List of Tables v 1. Introduction 1 2. System model 3 2.1 Heterogeneous cellular network with small moving cells 3 2.2 Signal-to-interference plus noise ratio (SINR) 4 2.3 FA Size 5 2.4 Traffic load 6 3. Resource allocation for SMCs 9 3.1 Previous works 9 3.2 Proposed resource allocation 12 3.2.1 Resource allocation based on the mean FA size 13 3.2.2 Resource allocation based on the peak FA size 15 3.3 Resource adjustment for SMCs 16 3.4 Overhead 17 4. Performance evaluation 19 5. Conclusions 26 References 27 1. 초 록 30Maste

MAC Scheduling Strategies in LTE Advanced

An Efficient scheduling algorithm at the data link layer is needed in multiuser systems to efficiently exploit the benefits of multiuser multiple input multiple output (MIMO). The 3G partnership programme (3GPP) does not specify any specific scheduling for Long Term Evolution (LTE) Advanced; we can have any one of the scheduling strategies applicable for LTE Advanced. There is substantial amount of literature on scheduling algorithms for multiuser wireless systems. In this paper, we are presenting various types of scheduling schemes of LTE Advanced, their advantages, and inefficiencies.Keywords – Scheduling, MIMO, LTE Advanced, Channel state information (CSI) , Adaptive modulation and coding (AMC)