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In this paper, a power consumption model for both macrocell and microcell base stations is proposed. This model is validated by temporal power measurements on actual base stations, and an excellent agreement is obtained. Furthermore, the power consumption's evolution during the day is investigated by means of these measurements. The energy efficiency of three different wireless technologies is compared namely mobile Worldwide Interoperability for Microwave Access, Long Term Evolution and High Speed Packet Access. With the model proposed, the deployment tool Green Radio Access Network Design is implemented, which allows to design an energy-efficient access network for a predefined area. In general and with the assumptions made, a macrocell base station consumes about 4.4 times more than a microcell base station. However, a microcell base station is less energy efficient than a macrocell base station because of its lower coverage range. Despite this, it is still useful to introduce them in the network as the same coverage can be obtained with a lower total power consumption than with a network where only macrocell base stations are used. Copyright © 2012 John Wiley & Sons, Ltd.

As both the bit rate required by applications on mobile devices and the number of those mobile devices are steadily growing, wireless access networks need to be expanded. As wireless networks also consume a lot of energy, it is important to develop energy-efficient wireless access networks in the near future. In this study, a capacity-based deployment tool for the design of energy-efficient wireless access networks is proposed. Capacity-based means that the network responds to the instantaneous bit rate requirements of the users active in the selected area. To the best of our knowledge, such a deployment tool for energy-efficient wireless access networks has never been presented before. This deployment tool is applied to a realistic case in Ghent, Belgium, to investigate three main functionalities incorporated in LTE-Advanced: carrier aggregation, heterogeneous deployments, and Multiple-Input Multiple-Output (MIMO). The results show that it is recommended to introduce femtocell base stations, supporting both MIMO and carrier aggregation, into the network (heterogeneous deployment) to reduce the network's power consumption. For the selected area and the assumptions made, this results in a power consumption reduction up to 70%. Introducing femtocell base stations without MIMO and carrier aggregation can already result in a significant power consumption reduction of 38%.

Nowadays, we are witnesses of fast penetration of high data-rate cellular networks such as the Long Term Evolution (LTE). With increasing average access data rates in mobile networks, also the requirements on networks providing backhaul for the wireless infrastructure are increasing. New radio interfaces are already capable of providing hundreds of Mbps over a single radio link between a base station and a user, which means that the future backhaul network should be able to provide a connection to base station sites in the order of Gbps. As optical access networks are able to provide a very high bandwidth practically almost independent on distance as well as high energy efficiency, it seems that a combination of mobile wireless access with optical access networks is a very promising integrated approach for a sustainable and efficient next generation ubiquitous access network. Wireless cellular and optical wired access networks provide synergies and complementary features. The main benefits of using a kind of wireless access are mobility and ubiquity while optical access networks provide high data rates, low power consumption and robustness. In this paper, we investigate various options for deploying LTE in urban areas with a particular emphasis on energy efficiency. For the purpose of evaluation, we apply an access network model to estimate both power consumption and achievable access data rates for various deployment scenarios and show results of a case study for the city of Vienna. The considered deployment scenarios are assessed regarding their potential for improving energy efficiency.

In this study, a power consumption model as a function of the traffic is developed for macrocell base stations based on measurements on an actual base station. This model allows us to develop energy-efficient wireless access networks by combining the Green radio access network design (GRAND) tool designed by the authors, which develops an always-on network with a minimal power consumption for a predefined area, and an algorithm that introduces power reducing techniques in the network such as sleep modes and cell zooming. Green-field deployments and optimization of existing networks are investigated. For a green-field deployment, it was found that introducing sleep modes and cell zooming in the network can reduce the power consumption by up to 14.4% compared to the network without sleep modes and cell zooming. Optimizing existing networks by applying GRAND (without sleep modes and cell zooming) results in a power consumption reduction of 34.5% compared to the original network. A careful selection of base station locations already results in a significant energy saving. Introducing sleep modes and cell zooming to the current networks results in a saving of 8%. Sleep modes and cell zooming are promising energy-saving techniques for future wireless networks.

Due to growing importance of wireless access and the steeply growing data volumes being transported, the power consumption of wireless access networks will become an important issue in the coming years. This paper presents a model for this power consumption and investigates three base station types: macrocell, microcell, and femtocell base stations. Based on these models, the coverage effectiveness of the three base station types is compared and the influence of some power reducing techniques such as sleep modes and MIMO (Multiple Input Multiple Output) is evaluated.

Femtocells are considered as an enabler for low power, high bit rate future mobile access networks. In this study, we look at them as a technology to cover an area with a high bit rate connectivity. From the evaluation it is clear that sleep modes are imperative to maximise the energy efficiency of the mobile access network. We evaluate the power reduction and wake up time of different sleep modes and apply them to the model in order to evaluate the influence of the power consumption of the mobile access network. We demonstrate that fast wake up times and low power sleep modes are essential in order to make femtocells a viable technology for mobile access networks.

The power consumption of wireless access networks will become an important issue in the coming years. In this study, the power consumption of base stations for mobile WiMAX (Worldwide Interoperability for Microwave Access), fixed WiMAX, UMTS (Universal Mobile Telecommunications System), HSPA (High-Speed Packet Access) and LTE (Long-Term Evolution) is modelled and related to the coverage. A new metric, the power consumption per covered area PC(area), is introduced, to compare the energy efficiency of the considered technologies for a basic reference configuration and a future extended configuration, which makes use of novel Multiple Input Multiple Output (MIMO) technology. The introduction of MIMO has a positive influence on the energy efficiency: for example, for a 4 x 4 MIMO system, PC(area) decreases with 63% for mobile WiMAX and with 50% for HSPA and LTE, compared to a Single Input Single Ouptut (SISO) system. However, a higher MIMO array size (i.e. a higher number of transmitting and receiving antennas) does not always result in a higher energy efficiency gain.

Nowadays, wireless access networks are a large contributor to the CO 2 emissions of ICT. Today, ICT is responsible for 4 % of the annual energy consumption and this number is expected to grow drastically in the coming years. The power consumption of these wireless access networks will thus become an important issue in the coming years. In this paper, the power consumption of wireless base stations for mobile WiMAX, HSPA and LTE is modelled and compared for a future scenario. For our research, we assume a suburban area and a physical bit rate of 10 Mbps. We compare the wireless technologies for a SISO and three MIMO systems. For each case, we give a ranking of the wireless technologies as a function of their power consumption, range and energy eff ciency. Based on these results, we cover a specif ed area with each technology and determine which technology is the best solution for the specif ed area. We also compare the power consumption of the wireless access networks with the power consumption of the wired access networks.

The power consumption of wireless access networks will become an important issue in the coming years. In this paper, the power consumption of base stations for mobile WiMAX, HSPA, and LTE is modelled. This power consumption is related to the coverage of the base station. The considered technologies are compared according to their energy efficiency for different bit rates at a bandwidth of 5 MHz. For this particular case and based on the assumptions of parameters of the specifications, HSPA is the least energy-efficient technology. Until a bit rate of 11 Mbps LTE is the most energy-efficient while for higher bit rates mobile WiMAX performs the best. Furthermore the influence of MIMO is investigated. A decrease of about 80 % for mobile WiMAX and about 74 % for HSPA and LTE for the power consumption per covered area is found for a 4×4 MIMO system compared to a SISO system. The introduction of MIMO has thus a positive influence on the energy efficiency of the considered technologies. The power consumption and coverage model for base stations is then used to develop a prediction tool for power consumption in wireless access networks.

The power consumption of wireless access networks will become an important issue in the coming years. In this paper the power consumption of base stations for mobile WiMAX, fixed WiMAX and UMTS is modelled. This power consumption is evaluated in relation to the coverage. For a physical bit rate of 2 Mbps, a power consumption of approximately 5600 W and a range of 1 km is obtained with UMTS. Fixed WiMAX covers 70 % and mobile WiMAX only 40 % of this range. However, fixed and mobile WiMAX consume roughly 50 % less than UMTS. In a suburban area and for a physical bitrate of 2 Mbps, fixed WiMAX base stations consume approximately 6 W per user, mobile WiMAX base stations 17 W per user, and UMTS base stations 5 W per user. The power consumption of these wireless access networks is compared with other access network technologies and research challenges concerning these access networks are presented.

In this paper, we present and address the problem of designing green LTE networks with Internet of Things (IoT) nodes. We consider the new NarrowBand-IoT (NB-IoT) wireless technology that will emerge in current and future access networks. The main objective is to reduce power consumption by responding to the instantaneous bit rate demand by the user and the IoT node. In this context, we apply emerging evolutionary algorithms to the above problem. More specifically, we apply the Teaching-Learning-Optimization (TLBO), the Jaya algorithm, and a hybrid algorithm. This hybrid algorithm named TLBO-Jaya uses concepts from both algorithms in an effective way. We compare and discuss the preliminary results of these algorithms.