www.ietdl.org Published in IET Science, Measurement and Technology Received on 3rd August 2010 doi: 10.1049/iet-smt.2010.0094 ISSN 1751-8822 Model for power consumption of wireless access networks M. Deruyck E. Tanghe W. Joseph W. Vereecken M. Pickavet L. Martens B. Dhoedt Department of Information Technology, Ghent University/IBBT, Gaston Crommenlaan 8 box 201, Ghent B-9050, Belgium E-mail: margot.deruyck@intec.ugent.be Abstract: 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 PCarea , 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 × 4 MIMO system, PCarea 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. 1 Introduction Recent studies have shown that the power consumption of ICT is 4% of the annual energy production [1]. More importantly, this number is expected to grow drastically in the coming years [1]. Furthermore, the radio access networks are large contributors to the CO2 emissions [1 – 3]. This indicates that the power consumption of wireless access networks, and more in particular the power consumption of the base stations, is going to become an important issue in the coming years. Nowadays, the base stations are responsible for roughly two-thirds of the total CO2 emissions of the wireless access networks. Etoh et al. [3] state that the daily energy consumption per customer is 0.83 Wh for a terminal and 120 Wh for the mobile network, which is a consumption ratio of terminal against network of about 1:150. The energy consumption of the terminals is thus negligible in comparison with the energy consumption of the networks. Therefore it is clear that one should focus on the reduction of energy consumption of base stations in wireless access networks as the terminals are already optimised in terms of energy consumption because they are powered by batteries. The objective of this paper is to model the power consumption of base stations of various wireless technologies and compare their energy efficiency against the coverage range. In order to determine the energy efficiency of the considered technologies, a new metric, namely the power consumption per covered area, is defined. The energy efficiency for mobile WiMAX (Worldwide Interoperability for Microwave Access), fixed WiMAX, UMTS (Universal Mobile Telecommunications System), HSPA (High-Speed Packet Access) and LTE (LongTerm Evolution) is compared for bit rates of 3 and 60 Mbps. Finally, the influence of Multiple Input Multiple Output (MIMO) is investigated. IET Sci. Meas. Technol., 2011, Vol. 5, Iss. 4, pp. 155–161 doi: 10.1049/iet-smt.2010.0094 In literature, some related work can be found. In [4 – 6], a power consumption model for a base station is proposed. However, in the cited work, it is very difficult to investigate the influence of the individual components of the base station on the total power consumption, as well as the influence of possible dependencies between the components of the base station. Furthermore, in the cited work only one technology is used to determine the power consumption. Our work will show that for the considered case and based on the assumptions made for the parameters, distinct differences in energy efficiency can be noticed between the considered technologies. The outline of the paper is as follows. In Section 2, a short overview of the considered technologies is given. In Section 3, the power consumption of a base station is modelled and related to the coverage. Section 4 gives some results obtained with the model from Section 3. In Section 5, the final conclusions are given. 2 Technologies For the wireless access networks, we investigate the power consumption of outdoor base stations for five different wireless technologies: mobile WiMAX [7], fixed WiMAX [8], UMTS [9], HSPA [10] and LTE [11]. We first give a short description of the different technologies. WiMAX is a wireless technology for broadband communication based on the IEEE 802.16 standard. For fixed WiMAX, we analyse the IEEE 802.16-2004 interface, operating in the 2 – 11 GHz band and developed for fixed wireless applications. For mobile WiMAX, we analyse the IEEE 802.16e interface, operating in the 2 – 6 GHz band and developed for mobile wireless applications. Fixed 155 & The Institution of Engineering and Technology 2011 www.ietdl.org WiMAX uses OFMDA (Orthogonal Frequency Division Multiple Access) whereas mobile WiMAX uses the novel SOFDMA (Scalable Orthogonal Frequency Division Multiple Access) technique which is derived from OFDMA and supports a wide range of bandwidths to flexibly address the need for various spectrum allocation and application requirements. UMTS is developed by ETSI (European Telecommunications Standardisation Institute) and operates in the 2.1 GHz band. UMTS has been specified as an integrated solution for mobile voice and data. It offers mobile operators significant capacity and broadband capabilities to support more voice and data consumers, especially in urban centres. UMTS uses W-CDMA (Wideband Code Division Multiple Access) as multiple access technique. HSPA is the successor of the widely deployed UMTS and works in the 2.1 GHz band. It promises higher data rates, increased cell and user throughput and reduced delay compared to UMTS. LTE is the newest wireless broadband technology. In December 2009, the world’s first publicly available LTEservice was started in Scandinavia [12]. LTE is marketed as the fourth generation (4G) of radio technologies. It uses SOFDMA as multiple access technique and thus supports variable bandwidths from 1.4 to 20 MHz, just like mobile WiMAX supports scalability. LTE uses the 2.6 GHz band. In the future, LTE will probably also use the 800 MHz band (digital dividend frequencies). 3 Theoretical power consumption and coverage model for wireless access 3.1 mobile stations) and the rectifier. The power consumption of these components should be multiplied with the number of supported sectors nsector when determining the power consumption of the base station. In contrary to [16, 17], it is assumed that the signal generator is part of the transceiver. This adaptation is based on the information retrieved from operators. Furthermore, a base station contains equipment that is common for all the sectors such as the air conditioning and the microwave link (responsible for communication with the backhaul network in case no fibre link is available). The distinction between the components per sector and the components common for all sectors is based on the information retrieved from operators. In Fig. 1, the equipment of the base station and the different notations for the power consumption Pel of the different components are indicated. The power consumption of each component is here assumed to be constant, except for the power amplifier and the air conditioning. The power consumption of the latter depends on the internal and ambient temperature of the base station cabinet [18]. We assumed an internal and ambient temperature of 258C. To model the power consumption of the power amplifier, the efficiency h of the power amplifier is defined, which is the ratio of the RF output power Pout/amp (in Watt) to the electrical input power Pel/amp of the power amplifier (in Watt) [19]. In Fig. 1, Pout/amp corresponds to the input power PTx of one sector antenna resulting in the following equation for the efficiency h: h= Power consumption of a base station A base station is here defined as the equipment needed to communicate with the mobile stations and with the backhaul network. In a base station, we typically find several power consuming components. Fig. 1 gives an overview of these components [13 – 15]. The area covered by a base station is called a cell. Each cell is further divided in a number of sectors. Each sector is covered by a sector antenna, which is a directional antenna with a sector-shaped radiation pattern. Some equipment is used for each sector such as the digital signal processing (responsible for system processing and coding), the power amplifier, the transceiver (responsible for receiving and sending of signals to the Fig. 1 Block diagram of the base station equipment 156 & The Institution of Engineering and Technology 2011 PTx Pel/amp (1) Based on PTx , we can calculate the power consumption Pel/amp of the power amplifier (in Watt) as follows Pel/amp = PTx h (2) Once the power consumption of the different components of the base station is known, the power consumption Pel of the base station (in Watt) can be determined Pel = nsector · (nTx · (Pel/amp + Pel/trans ) + Pel/proc + Pel/rect ) + Pel/micro + Pel/airco (3) with nsector being the number of sectors in the cell, and Pel/amp , Pel/trans , Pel/proc , Pel/rect , Pel/micro and Pel/airco are the power consumptions of the power amplifier, the transceiver, the digital signal processing, the rectifier, the microwave link (if present) and the air conditioning, respectively. In case MIMO is used, the base station needs the same number of power amplifiers and the same number of transceivers as the number of transmitting antennas [20]. In order to take the power consumption of this extra equipment into account, the power consumption of the power amplifier and the transceiver is multiplied by the number nTx of transmitting antennas for one sector. MIMO influences also the digital signal processing but this is, compared to the transceiver, negligible. Furthermore, (3) is only valid when one frequency is used per sector. Table 1 summarises the power consumption of the different components of a base station for the considered technologies. These values are retrieved from data sheets of various IET Sci. Meas. Technol., 2011, Vol. 5, Iss. 4, pp. 155 –161 doi: 10.1049/iet-smt.2010.0094 www.ietdl.org Table 1 Power consumption of the base station components for the considered technologies (mobile WiMAX, fixed WiMAX, UMTS, HSPA and LTE) Equipment digital signal processing power amplifier (SISO) power amplifier (MIMO) transceiver rectifier air conditioning microwave link Value Pel/proc h Pel/amp (max.) h Pel/amp (max.) Pel/trans Pel/rect Pel/airco Pel/micro 100 W 12.8% 156 W 11.54% 10.4 W 100 W 100 W 225 W 80 W manufacturers of network equipment and from standards [13, 21– 28]. For the power amplifier, the maximum power consumption is indicated. The power consumption of the digital signal processing and the transceiver are based on confidential data retrieved from an operator. The results presented in this paper depend on the values listed in Table 1. The most important source of power consumption is the air conditioning. In contrast to [16], the same air conditioning is used for all technologies. This adaptation is made based on the information retrieved from operators. Furthermore, a power amplifier with a more realistic efficiency was chosen for the reference configuration [13]. This power amplifier can be used for all the considered technologies because it supports the frequency of each considered technology and the RF output power of the power amplifier covers the needed input power of the antennas for each considered technology. Also the power amplifier for the extended configuration can be used for all the considered technologies. As a validation of our model, we compare the power consumption with available data and measurements. For a three-sector base station with one antenna per sector, Pel equal to 1672.6 W is found with (3) for UMTS, HSPA and LTE. In [13, 15], Pel of 1700 and 1500 W, respectively, are found for the traditional 3G base station, which is similar to the Pel obtained with our model. In [4], Pel for a one-sector base station with one antenna is 783 W. With our model, similarly, Pel ¼ 761 W is obtained. Furthermore, a good similarity between our Pel and confidential data from an operator about the power consumption of 3G base stations is obtained. 3.2 Calculation of the coverage range R of the base station The power consumption Pel of the base station is now related to the wireless range R covered by this base station. To this end, a link budget has to be constructed. A link budget takes all of the gains and the losses of the transmitter through the medium to the receiver into account. Firstly, we calculate the maximum allowable path loss PLmax (in dB) to which a transmitted signal can be subjected while still being detectable at the receiver. The path loss is the ratio of the radiated power to the received power of the signal; it includes all of the possible elements of loss associated with interactions between the propagating wave and any objects between the transmit and receive antennas [29]. To determine PLmax , the parameters of Table 2 are taken into account. Table 2 lists all the gains and losses that occur. These parameters are retrieved from the specifications and/or are typical values proposed by the operators IET Sci. Meas. Technol., 2011, Vol. 5, Iss. 4, pp. 155–161 doi: 10.1049/iet-smt.2010.0094 themselves in order to make a fair comparison between the considered technologies. Some of these parameters need a short explanation, for example, the fading margin. The fading margin accounts for temporal fading (e.g. varying weather conditions) and is determined based on the projected yearly availability of the system. The noise figure is a measure of degradation of the SNR (Signal-to-Noise Ratio) caused by components in the radio frequency signal chain. The receiver SNR determines the required SNR at the receiver for a certain BER (Bit Error Rate) and the bit rate. Since UMTS and HSPA use W-CDMA as multiple access technique, an extra gain needs to be taken into account. This gain is called the processing gain PG (in dB) and is defined as [30]   CR PG = −10 log(SP) = −10 log SR (4) with SP being the spreading factor, which is the ratio of the chip rate CR (in Mcps) to the symbol rate SR (in bps). The processing gain is thus the ratio of the spreaded (RF) bandwidth to the unspreaded (baseband) bandwidth. Also the input power of the antenna for UMTS and HSPA needs to be scaled according to the control overhead, the target load and the maximum number of users [31] TCH PTx = (1 − CL) · PTx TLNusers (5) TCH with PTx being the power reserved by the base station for the traffic channels. CL is the control overhead, TL the target load and Nusers the maximum number of users. PTx is used to determine the power consumption of the base station and TCH PTx is used to determine the range of the UMTS and HSPA base station (Table 2). For mobile WiMAX, fixed TCH WiMAX and LTE, PTx in Table 2 is equal to PTx because an OFDMA-based multiple access technology is used. Also, the user interference margin UIM (in dB) needs to be taken into account when using UMTS and HSPA [31] UIM = −10 · log10 (1 − TL) (6) with TL the target load. For mobile WiMAX, HSPA and LTE an extra gain, the MIMO gain GMIMO needs to be taken into account for the extended configuration (MIMO) (Section 4.3). Here, the theoretical MIMO gain GMIMO is considered [32] GMIMO = 10 log10 (nTx nRx ) (7) GMIMO in (7) might be an overestimation for some realistic cases [33], but (7) is used for all technologies to have a fair comparison. Once the maximum allowable path loss PLmax is known, the maximum range R (in metres) covered by the base station of a certain technology can be determined R = g−1 ((PLmax − SM)| f , hBS , hMS ) (8) with PLmax being the maximum allowable path loss (in dB), SM the shadowing margin (in dB), f the frequency (in Hz), hBS the height of the base station (in metres) and hMS the height of the mobile station (in metres). The shadowing margin depends on the standard deviation of the path loss 157 & The Institution of Engineering and Technology 2011 www.ietdl.org Table 2 Link budget table for technologies considered Parameter frequency input power of base station ptx effective input power of TCH base station PTx antenna gain of base station antenna gain of mobile station number of MIMO TX antennas number of MIMO RX antennas cyclic combining gain of base station soft handover gain feeder loss of base station feeder loss of mobile station fade margin yearly availability cell interference margin user interference margin bandwidth constellation receiver SNR number of used subcarriers number of total subcarriers noise figure of mobile station implementation loss of mobile station processing gain control overhead target load max. number of users duplexing building penetration loss [34] Mobile WiMAX Fixed WiMAX UMTS HSPA LTE Unit 2.5 35 3.5 35 2.1 43 2.1 43 2.6 43 GHz dBm 35 35 31.5 24.7 43 dBm 16 17 17.4 17.4 18 dBi 2 8 0 0 0 dBi 1, 2, 3, 4 1 1 1, 2, 3, 4 1, 2, 3, 4 – 1, 2, 3, 4 1 1 1, 2, 3, 4 1, 2, 3, 4 – 3 3 3 3 3 dB 0 0.5 0 0.5 1.5 2 1.5 0 0 2 dB dB 0 0 0 0 0 dB 10 99.995 2 10 99.995 0 10 99.995 0 10 99.995 2 10 99.995 2 dB % dB 0 0 6 9 0 dB 1.25 2/3 64-QAM 19 85 3.5 3/4 QPSK 11.2 201 5 PS 384 data service 7 1 5 3/4 QPSK 3.4 1 1.4 [2/3 16-QAM, 2/3 64-QAM] [19, 29.4] ([34]) 76 MHz – dB – 128 256 1 1 128 – 7 4.6 8 9 8 dB 2 0 0 0 0 dB – – – – TDD (Time Division Duplexing) 8.1 – – – – 10.0 0.25 0.75 4 12 0.25 0.875 75 – – – – dB – – – – 8.1 8.1 8.1 8.1 dB model, the coverage percentage and the outdoor standard deviation. Here, a coverage percentage of 90% is considered. The function g(.) depends on the used path loss model, for example, the HATA model and the Erceg model [35, 36]. In this paper, the Erceg C model is used as this is best suitable for suburban areas. The quantity before the ‘|’ in (8) is a variable and varies over a continuous interval, whereas the quantities after the ‘|’ are parameters that take only one discrete known value. 3.3 Parameter to quantify the power consumption and efficiency If multiple technologies are compared, it is very difficult to determine which one is the most energy efficient: one 158 & The Institution of Engineering and Technology 2011 technology could have higher power consumption but also a higher range, another one could have a smaller range but also a lower power consumption etc. Therefore the power consumption PCarea per covered area (in W/m2) is defined to quantify the power consumption and efficiency for different technologies Pel (9) pR2 with Pel being the power consumption of the entire base station (in Watt) and R the covered range (in m). This parameter allows us to compare the energy efficiency of different wireless technologies and to determine which one is the most energy efficient. The lower the PCarea , the more energy efficient the considered technology is. The PCarea = IET Sci. Meas. Technol., 2011, Vol. 5, Iss. 4, pp. 155 –161 doi: 10.1049/iet-smt.2010.0094 www.ietdl.org 60 Mbps are considered. Only mobile WiMAX and LTE support 60 Mbps. The different parameters can be found in Tables 1 – 3. For 60 Mbps, a 20 MHz channel is used. Mobile WiMAX uses 1440 out of 2048 subcarriers and LTE 1201. Furthermore, the 2/3 64-QAM modulation (19 dB receiver SNR for mobile WiMAX and 29.4 dB for LTE [37]) is used. Table 4 lists the results for R, Pel and PCarea . Based on the assumptions made for the parameters and 3 Mbps, UMTS is the most energy-efficient technology (lowest PCarea) followed by (in rising order for PCarea) fixed WiMAX, LTE, mobile WiMAX and HSPA. The power efficiency PCarea of UMTS and fixed WiMAX is considerably lower (,1 mW/m2) than those for mobile WiMAX, HSPA and LTE (2.4 – 3.5 mW/m2). UMTS performs better than fixed WiMAX because of its higher ranges (lower receiver SNR and the processing gain in Table 2). The higher power consumption Pel of UMTS is owing to the higher input power PTx of the antenna. Fixed WiMAX is more efficient than mobile WiMAX, HSPA and LTE because of its higher range (lower receiver SNR and higher antenna gain of the mobile station in Table 2) and its lower power consumption (lower PTx of the fixed WiMAX base station). Finally, LTE is more energy efficient than mobile WiMAX and HSPA because of its higher effective TCH input power PTx of the antenna resulting in a higher range. For 60 Mbps, mobile WiMAX performs better than LTE because of its higher range and lower power consumption. This higher range is caused by its lower receiver SNR. The power consumption is lower because of its higher PTx . Important to remark is that for different modulation schemes and coding rates, the power consumption Pel does not change [16]. However, a different range is obtained, which has a direct influence on PCarea . normalisation to the area allows us to make a fair comparison between the different technologies in terms of energy efficiency. It is assumed that the cells are circular. 4 4.1 Applications Configuration In this investigation, the base stations are placed outdoor in a suburban environment. Only macro cells with a base station antenna height of 30 m are considered. For the mobile stations, an indoor residential configuration with a WNIC (Wireless Network Interface Card) for a laptop for all technologies is considered except for fixed WiMAX, where we consider a residential gateway. Table 3 summarises the configuration parameters for all technologies described in Section 2. We also define two technical configurations for the outdoor base stations: a basic reference configuration and an extended configuration. All the considered technologies support the basic reference configuration. The extended configuration is only supported by mobile WiMAX, HSPA and LTE. In the basic reference configuration, one transmitting (Tx) and one receiving (Rx) antenna is considered, that is, a SISO (Single Input Single Ouput) system. In the extended configuration, both the base station and the receiver have multiple antennas. Six different MIMO systems are considered: 2 × 1 (2 Tx and 2 Rx), 2 × 2, 2 × 3, 3 × 3, 4 × 3 and 4 × 4 MIMO systems. The frequencies used for the link budget calculations of the different technologies are the following: 2.5 GHz for mobile WiMAX, 3.5 GHz for fixed WiMAX, 2.1 GHz for UMTS and HSPA and 2.6 GHz for LTE. 4.2 Comparison of the technologies considered In this section, the considered wireless technologies are compared for the reference configuration. In order to make a fair comparison, predefined bit rates of 3 Mbps and Table 3 Value area type number of sectors nsector height of a base station height of a mobile station coverage requirement path loss model shadowing margin Influence of MIMO In this section, the influence of MIMO on the energy efficiency is investigated. The considered technologies are compared for a 2 × 1, 2 × 2, 3 × 2, 3 × 3, 4 × 3 and 4 × 4 MIMO system (Section 4.1). Fig. 2 gives an overview of PCarea as a function of the chosen MIMO system for mobile WiMAX, HSPA and LTE. The energy efficiency gain is also indicated in the figure. The energy efficiency gain, EG, indicates how much (as a percentage) PCarea has decreased compared to the SISO system Configuration table under consideration Parameter Table 4 4.3 suburban 3 30 m 1.5 m 90% Erceg C 13.2 dB EG = PCarea/SISO − PCarea/MIMO · 100 PCarea/SISO (10) Comparison of the technologies considered for a physical bit rate of 3 Mbps and 60 Mbps Mobile WiMAX Fixed WiMAX UMTS HSPA LTE 3 Mbps bit rate [Mbps] R [m] Pel [W] PCarea [mW/m]2 3.6 342.5 1279.1 3.5 3.1 674.4 1279.1 0.9 3 846.1 1672.6 0.7 3.8 372.5 1672.6 3.8 3.2 470.6 1672.6 2.4 60 Mbps bit rate [Mbps] R [m] Pel [W] PCarea [mW/m2] 61.1 172.2 1279.1 13.7 – – – – – – – – – – – – 67.6 138.3 1672.6 27.8 IET Sci. Meas. Technol., 2011, Vol. 5, Iss. 4, pp. 155–161 doi: 10.1049/iet-smt.2010.0094 159 & The Institution of Engineering and Technology 2011 www.ietdl.org Fig. 2 Influence of 2 × 1, 2 × 2, 3 × 2, 3 × 3, 4 × 3 and 4 × 4 MIMO on PCarea Based on the assumptions made for the parameters and the considered cases, Fig. 2 shows that the energy efficiency increases when MIMO is introduced. The highest energy efficiency is obtained with a 4 × 4 MIMO system (up to 63%). The EG is the highest for mobile WiMAX. Compared to the SISO system, the area covered by each technology increases with 438%, because of an increase of 132% of the range, whereas the power consumption increases with only 95% for mobile WiMAX and 173% for HSPA and LTE. The increase in power consumption is lower for mobile WiMAX because of its lower input power PTx of the antenna (Table 2). This is also the reason why the highest EG are obtained with mobile WiMAX (34–63%) for all considered MIMO systems. Comparing the different MIMO systems reveals that a higher MIMO array size (i.e. more transmitting and/or more receiving antennas) does not always results in a higher energy efficiency. For mobile WiMAX, EG for a 2 × 2 and 3 × 2 MIMO system are approximately equal (51%). This can be explained as follows: The power consumption Pel of the base station for 2 × 2 MIMO is lower (1689.5 W against 2495.8 W for 3 × 2 MIMO) because only two transmitting antennas are used [see (3)]. However, the range is higher for the 3 × 2 MIMO system (794.4 m against 576.3 m for 2 × 2 MIMO) because of its higher MIMO gain [see (7)], resulting in similar values for PCarea and EG. Analogously for LTE, the 2 × 2 and 3 × 3 MIMO system have higher EG than the 3 × 2 and the 4 × 3 MIMO system, respectively. For HSPA even lower EG values for the 3 × 3 and 4 × 3 MIMO system than for the 3 × 2 MIMO system and the 3 × 3 MIMO system are obtained, respectively. 5 compared for the considered bit rates for a basic reference configuration and an extended future configuration. Lower PCarea values mean that the technology is more energy efficient. Based on the assumptions made for the parameters, the reference configuration and 3 Mbps, UMTS is the most energy-efficient technology followed by (in rising order of PCarea) fixed WiMAX, LTE, mobile WiMAX and HSPA. For 60 Mbps (only supported by mobile WiMAX and LTE), mobile WiMAX performs better. The introduction of MIMO has a positive influence on the energy efficiency. The biggest influence is obtained with a 4 × 4 MIMO system: PCarea increases up to 63% for mobile WiMAX and up to 50% for HSPA and LTE. Furthermore, a higher MIMO size does not always result in higher energy efficiency. Future research will consist of including microcells to cover smaller areas in the model of Section 3. Also the influence of load dependency on the range (cell breathing) and thus the power efficiency will be investigated. When there is little or no activity in the area of the base station, the base station could be switched off (sleep mode). Nowadays, this is not supported by the base station but this should be part of future research. The sleep modes have to be combined with an advanced management algorithm and will have a positive influence on the power consumption and energy efficiency. 6 Acknowledgment W. Joseph is a Post-Doctoral Fellow of the FWO-V (Research Foundation Flanders). Conclusions and future research In this paper, the power consumption for five different wireless technologies, namely mobile WiMAX, fixed WiMAX, UMTS, HSPA and LTE is investigated based on the parameter assumptions for the five technologies. This power consumption is then related to the coverage of the base station. The base stations (macro cells) are placed outdoor and for the mobile stations. An indoor residential scenario with a WNIC is considered, except for fixed WiMAX where a residential gateway is considered. The energy efficiency per covered area PCarea was defined and 160 & The Institution of Engineering and Technology 2011 7 References 1 Pickavet, M., Vereecken, W., Demeyer, S., et al.: ‘Worldwide energy needs for ICT: the rise of power-aware networking’. 2008 IEEE ANTS Conf., Bombay, India, December 2008, pp. 1– 3 2 Ericsson: Sustainable energy use in mobile communications’. White paper, August 2007 3 Etoh, M., Ohya, T., Nakayama, Y.: ‘Energy consumption issues on mobile network systems’. Int. Symp. Issues on Mobile Network Systems, 2008, pp. 365–368 4 Richter, F., Fehske, A., Fettweis, G.: ‘Energy efficiency aspects of base station deployment strategies for cellular networks’. IEEE 70th Vehicular Technology Conf. Fall (VTC 2009-Fall), 2009, pp. 1 –5 IET Sci. Meas. Technol., 2011, Vol. 5, Iss. 4, pp. 155 –161 doi: 10.1049/iet-smt.2010.0094 www.ietdl.org 5 Koutitas, G.: ‘Low carbon network planning’. European Wireless Conf., Lucca, Italy, April 2010, pp. 411–417 6 Micallef, G., Mogensen, P., Scheck, H.: ‘Cell size breathing and possibilities to introduce cell sleep mode’. European Wireless Conf., Lucca, Italy, April 2010, pp. 111–115 7 Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems: Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed bands and Corrigendum 1, IEEE Computer Society and the IEEE Microwave Theory and Techniques Society, February 2006. Available at www.ieee802.org/16 8 Air Interface for Fixed Broadband Wireless Access Systems, IEEE Computer Society and the IEEE Microwave Theory and Techniques Society, October 2004. Available at www.ieee802.org/16 9 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; UE Radio Transmission and Reception (TDD) (Release 1999), TR 25.102 v3.13.0, 3GPP, October 2006 10 3rd Generation Partnership Project: Technical Specification Group Radio Access Network: Physical layer aspects of UTRA High Speed Downlink Packet Access (Release 4), TR 25.848 v4.0.0., 3GPP, March 2001 11 LTE: 3rd Generation Partnership Project: Technical Specification Group Radio Access Network: Evolved Universal Terrestrial Radio Access (E-UTRA): User Equipment (UE) radio transmission and reception (TS 36.101 v9.1.0 Release 9), 3GPP, September 2009 12 TeliaSonera: ‘TeliaSonera first in the world with 4G services’, available at www.teliasonera.com/News-and-Archive/Press-releases/2009/TeliaSonerafirst-in-the-world-with-4G-services/, accessed December 2009 13 Barth, U.: ‘Wireless networks, EARTH research project’. ETSI Green Agenda Workshop, November 2009 14 Gildert, P.: ‘Power system efficiency in wireless communication’ (Ericsson, 2006) 15 Hérault, L.: ‘GreenWireless Communications eMobility GA1’. e-Mobility Workshop at the 4th Future Networks Concertation Meetings, Brussels, Belgium, September 2009 16 Deruyck, M., Vereecken, W., Tanghe, E., et al.: ‘Power consumption in wireless access networks’. European Wireless Conf., 2010, Lucca, Italy, April 2010, pp. 924– 931 17 Deruyck, M., Vereecken, W., Tanghe, E., et al.: ‘Comparison of power consumption of mobile WiMAX, HSPA and LTE access networks’. Ninth Conf. Telecommunication, Media and Internet TechnoEconomics (CTTE), 2010, Ghent, Belgium, June 2010, paper ID: 17 18 Pfannenberg, available at ‘http://www.pfannenbergusa.com/catalog/ catalog-downloads/2010Catalog.pdf’, 2010 IET Sci. Meas. Technol., 2011, Vol. 5, Iss. 4, pp. 155–161 doi: 10.1049/iet-smt.2010.0094 19 Raab, F., Asbeck, P., Cripps, S., et al.: ‘RF and microwave power amplifiers and transmitter technologies – Part 1’. High Frequency Electronics, 2003, pp. 22–36 20 Bhagavatula, R.H. Jr, Linehan, K.: ‘Performance evaluation of MIMO base station antenna designs’, Antenna Syst. Technol., 2008, 11, (6), pp. 14–17 21 Ophir RF model 5303009, 2010 22 Ophir RF model 5303025, 2010 23 Ophir RF model 5303075, 2010 24 Power-One S series, 2010 25 Daikin FUQ125BW13/R2Q125D7413, 2010 26 Allgon Microwave – AMR Transcend PLUS, 2010 27 Ceragon Networks – FibeAIR 1500P Family, 2010 28 Trangobroadbandnetworks – TrangoLINK – Giga, 2010 29 Saunders, S.: ‘Antennas and propagation for wireless communication systems’ (Wiley, 1999) 30 Krüger, R., Mellein, H.: ‘UMTS introduction and measurement’ (Rohde & Schwarz, 2004) 31 Hämäläinen, J.: ‘Cellular network planning and optimization – part VII: WCDMA link budget’ (Helsinki University of Technology, Course, 2008), Available at http://www.comlab.hut.fi/studies/3275/Cellularnet workplanning and optimization part8.pdf 32 Nuaymi, L.: ‘WiMAX technology for broadband wireless access’ (Wiley, 2007) 33 Deruyck, M., Tanghe, E., Joseph, W., Pareit, D., Moerman, I., Martens, L.: ‘Performance analysis of WiMAX for mobile applications’. IEEE Wireless Communications and Networking Conf., Sydney, Australia, April 2010, paper ID: T04S35P01 34 Plets, D., Joseph, W., Verloock, L., Martens, L., Gauderis, H., Deventer, E.: ‘Extensive penetration loss measurements and models for different building types for DVB-H in the UHF band’, IEEE Trans. Broadcast., 2009, 55, (2), pp. 213–222 35 Hata, M.: ‘Empirical formula for propagation loss in land mobile radio services’, IEEE Trans. Veh. Technol., 1980, 29, (3), pp. 317–325 36 Erceg, V., Greenstein, L., Tjandra, S., et al.: ‘An empirically based path loss model for wireless channels in suburban environments’, IEEE J. Sel. Areas Commun., 1999, 7, (7), pp. 1205– 1211 37 Abdul Basit, S.: ‘Dimensioning of the LTE network: description of models and tools, coverage and capacity estimation of 3GPP long term evolution radio interface’. Master’s thesis, Helsinki Unversity of Technology, February 2009 161 & The Institution of Engineering and Technology 2011