4.1 the Number of Femto and Macro Cell Base Stations

Abstract Nowadays the traffic demand grows fast that requires careful chosen deployment strategy to increase capacity, but save investments. Another important subject is to save a power consumed mostly by base station itself and its backhaul network. So, what type of base stations must be chosen, what spectrum characteristics it has and what backhaul link is connected to it. All this aspects requires different approaches, as they have different capacity and cover characteristics. The motivation is to compare the solutions using different base station types and various backhaul solutions. The question if the spectral efficiency allows to increase the traffic throughput, it would decrease or increase power consumption and cost. The modern technologies propose several options, ones of them are macro cellar and femtocell network. The macro cell has a great ability to cover a big area, while the femtocell has a good capacity possibilities. Moreover, femtocell partially are paid and installed by end-users that decrease the installation and electricity cost for operators. However, operator can reuse existed sites which decrease investment cost of macrocellular network. So, the first milestone is to find the way how to fairly compare two different types of technologies. In this thesis the proposed scenario is composed in a very careful way to predict demand types, base stations possibilities and characteristics as well as the backhaul architecture. Then the more accurate model to deploy a femtocellular network has been described in detail. The more detailed cost strategy is introduced for backhaul solutions and described in detail. The power consumption calculations has been described in more clear way, to show the range of metrics, what value should it has: negative or positive. Some formulas is remade to reach more correct results. Another milestone is to bring all parameters to unique format that has been done to achieve right results. In the microwave backhaul solution, the topology case added and carefully i described, because every topology case requires different formulas, in this thesis, the calculation steps for star and ring topologies presented. Steps how to calculate the base station radius depends on power characteristics of base station is provided. Since this thesis introduces improvements in several points, It is good guide to keep in track the received results and control the calculation process. ii Acknowledgments I would like to thank my supervisor Ashraf and for all help and valuable feedback, as well as discussions and providing me with ideas and references for this research. I would also like to thank Jan Markendahl for advising me a choice of a research field, Cicek Cavdar for advices and being helpful and Sibel Tombaz for presenting a related work in the beginning of research. Ashraf Awadelakrim Widaa has been a good academic supervisor who provided me with valuable feedback of the report and presentations. I am thankful to family for a support and to my closest friends. iii iv Content 1 Introduction 1 1.1 Background. 1 1.2 Literature review . 2 1.3 Research Questions and problem formulation . 4 2 Network architecture 8 2.1 General description of the mobile network architecture. 8 2.2 Radio Access Network. 9 2.3 Backhaul solutions and topologies . 10 2.3.1 Fiber optic solution. 11 2.3.2 Microwave solution. 12 2.3.3 Topologies . 13 2.3.4 Core network . 14 3 Deployment methodology 16 3.1 General description. 16 3.1.1 Coverage demand and assumptions . 17 3.1.2 Capacity demand and assumptions. 18 3.2 Cost and Power Models . 19 3.2.1 Cost model . 21 3.2.1.1 The number of cells to deploy the network . 21 3.2.2 Power model . 24 3.2.2.1 The power model of one base station . 24 3.2.2.2 The power model of backhaul part of network . 25 3.3.2.2.1 Fiber-based backhaul solution . 25 v 3.3.2.2.2 Microwave-based backhaul . 26 4 Results and discussion 30 4.1 The number of femtocell and macro cell base stations. 30 4.2 Power consumption results. 32 4.2.1 Result presentation . 32 4.2.2 Discussion. 35 4.3 Cost results. 37 4.3.1 Result presentation . 37 4.3.2 Discussion . 40 5 Conclusion and future work . 43 References . 47 vi vii List of Figures and Tables Fig. 2.1. Brief architecture of network architecture. .. 8 Fig. 2.2. The difference between thr macro cell and femtocell . 9 Fig. 2.3. The nowadays choice of modern backhaul technologies . 10 Fig. 2.4. Brief architecture of network with backhaul . 11 Fig. 2.5. AGGP-aggregation point supplies several base stations via a wireless link. 12 Fig. 2.6. Backhaul topologies . .. .. 13 Fig. 3.1. Deployment area. 18 Fig. 3.2. Wall attenuation (WA) influence on a radius (R1>R2) of one base station . 22 Fig. 3.3. a) horizontal view, the floor area is 1 square km ; b) vertical planning, 5 floors 23 Fig. 3.4. Tree topology. 27 Fig. 4.1. The number of macro base stations to meet the capacity demand. 31 Fig. 4.2. The number of femto base stations to meet the capacity demand. 31 Fig. 4.3. Detailed view of power consumption of macro base station . 33 Fig. 4.4. Macro cellular network. Comparison of macro cellular network power consumption using microwave or fiber solutions.. .. .. .. .. .. .. 33 Fig. 4.5. Power consumption of one base station. Femto cell.. .. .. .. .. .. 34 Fig. 4.6. Femtocellular network power consumption. Comparison of microwave and fiber solutions. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 35 Fig. 4.7. Cost of macrocellular network with a fiber backhaul 1st year. Comparison of the green deployment(all sites are new) versus using existing macrocell sites.... 37 Fig. 4.8. Net Present value of macrocellular network with fiber backhaul. Comparison of the green deployment(all sites are new) versus using existing macrocell sites.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 38 Fig. 4.9. Cost of femtocellular network with a fiber backhaul, 1st year. .. .. .. 38 Fig. 4.10. NPV of femtocellular network with a fiber backhaul . .. .. .. .. .. 39 Fig. 4.11. NPV of macrocellular network with a microwave backhaul. Comparison of the green deployment(all sites are new) versus using existing macrocell sites... 39 Fig. 4.12. NPV of femtocellular network with a microwave backhaul. .. .. .. .. 40 viii ix List of Acronyms and Abbreviations BS Base station BW Bandwidth CAPEX The investment cost dB Decibels, the unit to measure the power consumption EARTH Energy Aware Radio & network tecHnologies Gbps Gbits per second NPV Net present value O&M Operation and Maintenance OPEX Running cost TRX Transceiver QoS Quality of service WA Wall attenuation x xi CHAPTER 1 Introduction This chapter gives a brief introduction to the description of research questions along with a definition of the research gap considered in this thesis. The project’s scope, related works, research questions and methodology are described as well. 1.1 Background The tremendous increase of data traffic usage of mobile and wireless broadband motivate companies to look for different solutions and new technology. Companies want to spend less for more powerful technology. In order to support a growing demand, there are 3G and 4G technologies that are “hungry” for spectrum, but it is a high expenditure to buy a license thus one solution is to look for improvements in the hardware level with regard to spectral efficiency. The network cost differs depending on spectral efficiency, bandwidth, frequency and other factors. These factors is determined in this work considering coverage and capacity demand which supposed to have different approaches and base station technology and backhaul. It means the motivation of thesis is to consider the influence of these factors on the final cost and final power consumption. Nowadays, the question of power consumption becomes more popular due to the climate issue. According to research [1], 0.5 percent of global energy consumption is consumed by mobile networks today and the number is projected to increase manifold in the close future. It 1 arises a question what type of base stations consumes less power. Since base station sites are responsible for 80 % of the energy consumption [2]. However, even if one type of base station can consume less than another, it does not mean that it is the same when operator begin planning a whole network with backhaul. An interesting question is about what type of base stations is better to choose, femto or macro cells and what technology is better to use with them. So there is the possibility to decrease power consumption on the architecture level, but it is also important to take into account the backhaul solution and its power consumption model and cost model as well. Backhaul solution for indoor usage includes a topology and technology compromise that is required to be cost and power efficient and able to support a capacity growth with fair access to all users. These problems meet a question what required number of base stations is needed to meet user demands which in turn depends on coverage and data requirements in the chosen scenario. The increasing trend of data usage does not allow the operator to stay with the same type and quantity of technologies, expansion of broadband access territory is necessary. Some literature claim that new technologies must be implemented that requires deployment from the scratch, another source [3] claim that it is necessary first to consider the thought of upgrading the existing network infrastructure. Steps should be taken as soon as possible, but what steps should be taken here? The problem is that an inaccurate methodology can affect the quality of service (QoS). The calculation steps are required to make a plan of network, but it is hard to find it in a well described and organized order.

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