Portal de Periódicos da CAPES

Investigation of Open-Loop Transmit Power Control Parameters for Homogeneous and Heterogeneous Small-Cell Uplinks

2018; Electronics and Telecommunications Research Institute; Volume: 40; Issue: 1 Linguagem: Inglês

10.4218/etrij.2017-0191

2233-7326

Amir Haider, Rashmi Sharan Sinha, Seung‐Hoon Hwang,

Power Line Communications and Noise

ETRI JournalVolume 40, Issue 1 p. 51-60 ArticleFree Access Investigation of Open-Loop Transmit Power Control Parameters for Homogeneous and Heterogeneous Small-Cell Uplinks Amir Haider, Amir HaiderSearch for more papers by this authorRashmi Sharan Sinha, Rashmi Sharan SinhaSearch for more papers by this authorSeung-Hoon Hwang, Corresponding Author Seung-Hoon Hwang shwang@dongguk.edu orcid.org/0000-0001-7629-7865 Search for more papers by this author Amir Haider, Amir HaiderSearch for more papers by this authorRashmi Sharan Sinha, Rashmi Sharan SinhaSearch for more papers by this authorSeung-Hoon Hwang, Corresponding Author Seung-Hoon Hwang shwang@dongguk.edu orcid.org/0000-0001-7629-7865 Search for more papers by this author First published: 15 February 2018 https://doi.org/10.4218/etrij.2017-0191Citations: 9 Amir Haider (amirhaider@dongguk.edu), Rashmi Sharan Sinha (rashmisinha@dongguk.edu), and Seung-Hoon Hwang (corresponding author, shwang@dongguk.edu) are with the Division of Electronics and Electrical Engineering, Dongguk University, Seoul, Rep. of Korea. AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract In Long Term Evolution (LTE) cellular networks, the transmit power control (TPC) mechanism consists of two parts: the open loop (OL) and closed loop. Most cellular networks consider OL/TPC because of its simple implementation and low operation cost. The analysis of OL/TPC parameters is essential for efficient resource management from the cellular operator's viewpoint. In this work, the impact of the OL/TPC parameters is investigated for homogeneous small cells and heterogeneous small-cell/macrocell network environments. A mathematical model is derived to compute the transmit power at the user equipment, the received power at the eNodeB, the interference in the network, and the received signal-to-interference ratio. Using the analytical platform, the effects of the OL/TPC parameters on the system performance in LTE networks are investigated. Numerical results show that, in order to achieve the best performance, it is appropriate to choose αsmall = 1 and Po-small = –100 dBm in a homogenous small-cell network. Further, the selections of αsmall = 1 and Po-small = –100 dBm in the small cells and αmacro = 0.8 and Po-macro = –100 dBm in the macrocells seem to be suitable for heterogeneous network deployment. 1 Introduction Long Term Evolution (LTE) was introduced in the Release 8 specification of the Third Generation Partnership Project (3GPP), in order to accommodate the high-data-rate and low-latency requirements for cellular networks. Owing to the rapid increase in mobile broadband traffic, the need for network densification has become vital for radio access networks 1. With additional network nodes per unit area, the distance between the eNodeB and the user equipment (UE) can be minimized, which results in a link-budget improvement 2. One of the major challenges in the LTE network is intracell and intercell interference. For homogenous small-cell deployment, several interference mitigation schemes have been proposed in 3-5, which mostly focus on the downlink. For the uplink, the interference should be emphasized since it crucially impacts the network performance. For heterogeneous network (HetNet) deployment, the interference scenario becomes more complex owing to large differences between the transmit powers of the macrocell and small-cell layers. Therefore, intercell interference management plays a key role in HetNet performance 6. Most LTE networks adopt a frequency reuse factor of unity. Therefore, the network is prone to intercell interference. Thus, the 3GPP standard introduced transmit power control (TPC) to enable power control in both the downlink and uplink for LTE 7. In particular, the precise control mechanism for the UE uplink transmission power is emphasized to mitigate the adverse impact of interference on the network performance 8. Uplink TPC is initiated at the UE on the basis of the information in the downlink configurations by the eNodeB. There are two parts of the TPC mechanism in an LTE uplink, that is, the open loop (OL) and closed loop (CL). OL/TPC determines the initial power settings of the network, whereas CL/TPC aims to correct the errors in OL/TPC configurations. That is, OL/TPC compensates for the path loss and shadowing. Meanwhile, CL/TPC tends to mitigate fast fading 9. Most cellular networks consider OL/TPC because of its simple implementation and low operation cost. Therefore, in this work, only OL/TPC is taken into account. The 3GPP specification defines the UE transmit power PTx (dBm) for an LTE-A uplink as 10: (1) Pmax is the maximum allowable transmit power for the UE. M is the number of physical resource blocks (PRBs). For simplicity, M is set to 1 in this study. Po is a cell/UE-specific parameter. Po is assumed to be cell-specific in this study. α is the path-loss compensation factor. PL is the path loss between the UE and the serving eNodeB. ∆mcs and f(i) are the CL/TPC parameters defining the modulation and coding scheme and closed-loop correction, respectively, as defined in the 3GPP standards. While analyzing the OL/TPC, ∆mcs and f(i) are assumed to be zero. It is necessary to mention the role of the path-loss compensation factor. For α = 1, the path loss is "fully compensated." For lower values of α, the path loss is only "partially compensated" and called fractional power control (FPC). Specifically, α = 0 indicates "no power control." A higher value for α results in an increase in the transmit power and consequently higher intercell interference, which is mainly caused by the cell edge users. A lower value of α results in a decrease in the transmit power and thus reduces interference by the cell edge user, but it may degrade the performance. In this study, the parameters α and Po are both assumed to be cell-specific, although the standard allows Po to also be UE-specific. However, the 3GPP specification does not specify how to set these parameters to achieve proper network performance. In the literature, many studies have been carried out regarding the OL/TPC parameters in homogenous LTE and HetNet scenarios. Reference 11 described LTE uplink power control and analyzed its impact on the system performance. For a homogenous macrocell environment, a path-loss compensation factor αmacro of 0.8 was selected as the optimum value for FPC. However, the optimum value needs to be revisited in a homogeneous small-cell environment because of the cell size reduction. Reference 12 proposed an improved open-loop power control scheme for the LTE uplink, which applied a different value of αmacro for each group of users experiencing similar channel conditions. However, such an approach may not be feasible since the path-loss compensation factor is cell-specific in the LTE standard 10. In 13, the impact of the selection of the OL/TPC parameters on the network congestion in subway areas was described, where the proper tuning of the parameters was able to provide congestion relief. Our previous work 14 analyzed the impacts of αsmall and Po-small on the UE transmission power for a homogenous small-cell network, where a higher value of αsmall can be chosen, such as 0.9 or 1.0, since the UE transmit power becomes smaller than that in the macrocell case, as the path loss decreases with the reduction in the cell size. Therefore, in this study, we further extend the analysis to homogenous small-cell network deployment. For HetNet deployment, a UE-specific TPC algorithm was proposed in 15, where the interference was computed by the ratio of the UE-specific average interference to the average eNodeB interference. In 16, the impact of the OL/TPC parameters on the performance of LTE UL in a HetNet environment including the cell range extension for a picocell was analyzed. A brute-force search was applied to determine the optimum PC parameters without investigating their tendency in both homogeneous and HetNet environments. Additionally, the same fractional path-loss compensation factor was suggested for macrocell and picocell layers. That is, the same settings for both layers were considered. Reference 17 presented a detailed survey of power control schemes for an LTE uplink. However, it focused only on the selection of the value of α. Furthermore, the same value of α = 0.7 was assumed for both macrocells and small cells. It is necessary to consider different values of α for small cells and macrocells, as a higher value of α may be selected for the small cells 18. In addition, 19 analyzed the different values of Po for macrocells and small cells, where –90 dBm and –70 dBm were selected for the macrocell and small cell, respectively. However, the same value of α = 0.7 was assumed for both macrocells and small cells. Therefore, it is necessary to investigate the impact of the simultaneous variation in both α and Po on the network performances. Even though the uplink OL/TPC was described in a technical document 10, the specific value was not known. Thus, from the viewpoint of implementation, it is very important to know the information of parameter values such as α and Po. To the best of our knowledge, setting the parameter values for the UL OL/TPC in terms of both α and Po has not been intensively investigated. Additionally, such initial parameter settings are essential for network operators. Therefore, in this work, the impact of the OL/TPC parameters is investigated for both homogeneous small-cell and HetNet environments. Furthermore, for the OL/TPC in a HetNet, it is essential to analyze the individual and combined impacts of the variations in the macrocell and small-cell parameters on the network performance. A mathematical model is derived in order to compute the transmit power at a UE, the received power at an eNodeB, the interference in the network, and the received signal-to-interference ratio (SIR). By using this analytical platform, the OL/TPC parameters for the LTE networks are calculated. The rest of this paper is organized as follows. Section II presents a network model and its performance analysis. Section III presents the numerical results. Finally, Section IV concludes the paper. 2 Network Model and Performance Analysis We assume two scenarios for the small-cell uplink. One is a homogeneous small-cell network, and the other is a HetNet. We analyze the performance for both scenarios in terms of the UE transmit power, eNodeB received power, interference, and received SIR. 2.1 Homogenous Small-Cell Scenario This section considers homogenous small-cell deployment, where 19 small cells are uniformly distributed, as shown in the network in Fig. 1. The analysis is focused on the uplink for the central small cell surrounded by two tiers of small cells. In order to analyze the performance, the fluid model in 20 is employed. At the eNodeB, omnidirectional antennas are modeled to provide network coverage in each cell. The small cell radius is R = 200 m in the network range of Rnt = 1,000 m. Generally, a uniform UE distribution is assumed for the analysis of the OL/TPC settings in the network 21 since it provides a better insight for modeling and analyzing the network 22. Therefore, the UE distribution is assumed to be uniform in the small-cell area 23. The performance of the OL/TPC is analyzed in terms of the parameters α and Po. Figure 1Open in figure viewerPowerPoint Fluid model for homogenous small-cell deployment. 2.1.1 Transmit and Receive Powers For the homogenous small-cell environment, the uplink transmit power PTx-small (dBm) is given by (2)where Po-small is Po for the small cells, and αsmall is α for the small cells. The received power PRx-small (dBm) at the eNodeB can be derived from (2): (3)Note that we focus on the free-space model for path-loss estimation 24. The mathematical expression for the free-space model is given as (4)where r is the distance from the UE to the eNodeB in meters, and fMHz is the operating frequency. Equation (4) can be rewritten in order to calculate the distance from the UE to its serving eNodeB when the corresponding path loss and frequency values are known: (5) 2.1.2 Interference In Fig. 1, the central small cell with a radius of R is surrounded by two interfering rings at a distance of 2nR (n = 1, 2). The network size is expressed as Rnt = (2Ni + 1)R, where Ni represents the number of interfering rings. In this paper, two interfering rings are assumed. Note that the first ring of interfering cells is located between R and 3R, and the second ring exists between 3R and 5R. Figure 2 presents the fluid model for the interference calculation. The UE density of ρue is assumed to be uniform in each cell such that ρue = 1/(πR2). Consider a UE u scheduled by the central small cell eNodeB b. From (3), the received power at eNodeB b from UE u is written as (6)where po-small (mW) is the target received power, and plu,b is the path loss between UE u and eNodeB b. Since the frequency reuse factor is assumed to be one, UE u suffers external interference due to one UE per PRB in each neighboring cell. Therefore, the small-cell interference expression is approximated by (7)where u, b designates UE u scheduled by eNodeB b. Moreover, the path loss pl can be expressed in terms of the path gain pg where pg = 1/pl. In this work, we assume that the path loss is only dependent on the distance r between the UE and the eNodeB. Therefore, the path gain can be given as (8)where A is a constant and η = 3.5 is the path-loss coefficient. Consider user v scheduled by eNodeB c, which is located on the first ring of the interfering small cells at a distance r ∈ [R; 2R] from eNodeB b. Figure 2 clearly shows that user v is located at a distance of 2R – r from eNodeB c. The interference offered by the small area 2πrdr around UE v is . Similarly, if UE v is located in the region of the first interfering ring, that is, r ∈ [2R; 3R], it is at a distance r – 2R from eNodeB c. Hence, the interference offered now by the small area 2πrdr around UE v can be estimated to be . Therefore, the generalized expression for the interference offered by the nth interfering ring to the central small cell can be given as (9) Figure 2Open in figure viewerPowerPoint Fluid model for the interference calculation. The total interference offered to the central small cell can be approximated as (10) 2.1.3 Received SIR The received SIR for user u can be obtained by dividing (6) by (10): (11) 2.2 HetNet (Small Cell/Macrocell) Scenario This section considers HetNet deployment, where all of the parameters are the same as those of the homogeneous small scenario, except for the additional consideration of the macrocell ranging to 1,000 m. Figure 3 shows the network model for HetNet deployment. The small cells are assumed to be uniformly distributed in a macrocell. Table 1 summarizes the system parameters for both the homogeneous small-cell and HetNet scenarios. Figure 3Open in figure viewerPowerPoint Fluid model for HetNet deployment. Table 1. System parameters Parameter Homogenous small network Heterogeneous network Number of cells 19 small cells 19 small cells, 1 macrocell Cell radius Small-cell radius R = 200 m Small-cell radius R = 200 m, Macrocell radius = 5R = Rnt = 1,000 m UE distribution Uniform distribution Path-loss model Free-space model, PL = 32.45 + 20log10(r) + 20log10(fMHz) Antenna type at eNodeB Omnidirectional antenna Path-loss compensation factor 'α' range αsmall = 0.7, 0.8, 0.9, 1 αsmall = 0.7, 0.8, 0.9, 1αmacro = 0.8, 0.9, 1 Po range (dBm) Po-small = –60, –70, –80, –90, –100 Po-small = –60, –70, –80, –90, –100Po-macro = –60, –70, –80, –90, –100 2.2.1 Transmit and Receive Powers In the HetNet deployment, the uplink UE transmit and eNodeB received powers in the small cells are the same values as those in the homogenous small-cell deployment (see (2) and (3)). Therefore, we additionally consider the macrocell case. For the macrocell, the uplink UE transmit power PTx-macro (dBm) is given by (12) The received power PRx-macro (dBm) at the eNodeB is (13) 2.2.2 Interference For the HetNet deployment, only one macrocell is under consideration. Therefore, the interference experienced by the central small cell due to the macrocell can be formulated from (7) by (14) The total interferences in the HetNet environment can then be given as (15) 2.2.3 Received SIR The received SIR for user u in the HetNet environment can be obtained by dividing (6) by (15): (16) The impacts of noise and shadowing are not considered in this analysis. If the impacts of shadowing and noise need to be included, the variation presented in 25 can be expected. 3 Numerical Results In this section, analyses of the OL/TPC performance of the homogeneous small-cell and HetNet deployments are presented. For both scenarios, the network performance is quantified in terms of the UE transmit power, the received power at the eNodeB, and the received SIR. It would be beneficial for the UE to transmit with the lowest power, maintaining an acceptable level of the received SIR. 3.1 Homogenous Small-Cell Scenario When Po-small is kept constant and the path-loss compensation factor αsmall is varied from 0.7 to 1.0 in the homogenous small-cell deployment, the UE transmit power is analyzed as a function of the distance using (2). Po-small is set to –100 dBm since further decreases in Po-small may result in a received signal power below the dynamic range and thus an unacceptable received SIR at the eNodeB 26. Figure 4 indicates that for αsmall = 1.0, the transmit power becomes the maximum value, while as αsmall decreases, it decreases. This shows that the FPC decreases the UE transmit power; thus, it decreases the interference to the other cells. In addition, the UE transmit power increases with the distance from the eNodeB. The impact of variation in Po-small on the UE transmit power is analyzed when αsmall = 1.0. Figure 5 shows that the transmit power increases at a higher value of Po-small. Note that the transmit power becomes flat around a distance of 140 m when Po-small = –60 dBm since the UE transmit power is limited to 23 dBm. A comparison of Figs. 4 and 5 shows that the variation in αsmall results in a variation in the UE transmit power of around 25 dBm; meanwhile, the variation in Po-small results in a variation of around 38 dBm. Furthermore, the UE transmit power ranges from –80 dBm to –10 dBm for the variation in αsmall, and it ranges from –60 dBm to 30 dBm for the variation in Po-small. Therefore, it is necessary to find the proper combination of OL/TPC parameters that may optimize the network performance. Figure 4Open in figure viewerPowerPoint UE transmit power versus the distance as a function of αsmall in the homogenous small-cell deployment. Figure 5Open in figure viewerPowerPoint UE transmit power versus the distance as a function of Po-small in the homogenous small-cell deployment. Next, both αsmall and Po-small are varied. Figure 6 shows that the parameter set of αsmall = 1 and Po-small = –100 dBm results in the lowest UE transmit power. We can deduce that the optimum OL/TPC parameter set is a lower Po-small value and higher αsmall value. By using (3), the received power at the eNodeB is plotted as a function of αsmall and Po-small in Fig. 7. Note that for αsmall = 1 and Po-small = –100 dBm, the received power at the eNodeB is the same regardless of the distance since the path loss is fully compensated. It is clear that the impact of the parameter set is more influential when the UE is close to eNodeB. In order to calculate the received SIR at the eNodeB, the interference generated in the network is calculated according to (10). Figure 8 shows the interference levels as a function of different values of Po-small and αsmall. This shows that a lower value of Po-small results in less interference. Note that as αsmall increases, the interference increases since the FPC no longer provides benefits. Figure 6Open in figure viewerPowerPoint UE transmit power versus the distance as a function of αsmall and Po-small in the homogenous small-cell deployment. Figure 7Open in figure viewerPowerPoint eNodeB receive power versus the distance as a function of αsmall and Po-small in the homogenous small-cell deployment. Figure 8Open in figure viewerPowerPoint Interference versus αsmall as a function of Po-small in the homogenous small-cell deployment. In Fig. 9, the received SIR is calculated using (11) for the homogenous small-cell deployment. This shows that the parameters of αsmall = 1 and Po-small = –100 dBm give a constant received SIR e around 4 dB. In addition, it shows that for the other values of αsmall and Po-small, the SIR becomes larger when the UE is near the eNodeB and becomes smaller when the UE is far from the eNodeB. Note that there is a crossing point at a distance of around 40 m. This means that when the distance is closer than 40 m, the signal power is more dominant than the interference power. Meanwhile, as the UE approaches the cell edge, the interference becomes the dominant factor. Such a tendency diminishes as αsmall increases and Po-small decreases. Figure 9Open in figure viewerPowerPoint SIR versus the distance as a function of αsmall and Po-small in the homogenous small-cell deployment. 3.2 HetNet (Small Cell/Macrocell) Scenario In the HetNet environment where small cells coexist with macrocells, it is expected that the small cells carry most of the traffic load, and the macrocells support the backbone network. Therefore, in this study, we focus on the optimization of the performance of the small cells. The interference is now calculated for the macrocell according to (14) since it has been analyzed for the small cell. Figure 10 presents the HetNet interference as a function of αmacro and Po-macro using (15) when αsmall = 1 and Po-small = –100 dBm. This indicates that when αmacro is small, such as zero, almost the same interference results. However, when αmacro becomes larger, the interference increases. This confirms that the FPC is influential in macrocell environments. Figure 11 analyses the impacts of variations in αsmall and Po-small on the received SIR in the HetNet when αmacro = 1 and Po-macro = –100 dBm. Comparing Figs. 9 and 11, the macrocell interference degrades the SIR performance since the SIR distribution from –2 dB to 17 dB is changed to the interval of –3 dB to 11 dB. Note that the SIR shows similar performance of around –1 dB at the cell edge, even though it is improved when the UE is located very close to the eNodeB. This means that αmacro = 1 results in high interference, and a lower αmacro value may be preferable. Using (16), the received SIR in the HetNet is presented in Fig. 12 when αmacro = 0.8 and Po-macro = –100 dBm. Note that the received SIR appears to be similar to that in Fig. 9. Comparing Figs. 11 and 12, the SIR for αsmall = 1 is significantly improved, and the crossing point moves close to the eNodeB. This indicates that from the optimum operating point of view of the OL/TPC, a lower αmacro and higher αsmall combination would be generally preferred when both Po-small and Po-macro are –100 dBm. Additionally, it is shown that a lower αsmall and higher Po-small provide an SIR improvement when the UE is close to the eNodeB, even though the service quality for cell edge users becomes lower. Figure 10Open in figure viewerPowerPoint Interference versus αmacro as a function of Po-macro in the HetNet. Figure 11Open in figure viewerPowerPoint SIR versus the distance as a function of αsmall and Po-small in the HetNet for αmacro = 1.0. Figure 12Open in figure viewerPowerPoint SIR versus the distance as a function of αsmall and Po-small in the HetNet for αmacro = 0.8. 4 Conclusion In this paper, OL/TPC in the LTE uplink for both homogenous small-cell and HetNet environments were analyzed in terms of the UE transmit power, eNodeB received power, interference, and received SIR. The numerical results showed that a different combination of OL/TPC parameters, such as a lower Po-small and higher αsmall, was able to optimize the homogeneous small-cell network performance. More specifically, the combination of αsmall = 1 and Po-small = –100 dBm was proposed as an appropriate choice for the homogenous small-cell network. Meanwhile, for the HetNet deployment, αmacro = 0.8 and Po-macro = –100 dBm in the macrocell were suitable when the small-cell parameters were the same since the FPC was influential in the macrocell environment. Additionally, it was shown that from a network operation point of view for the OL/TPC, a lower αmacro and higher αsmall combination would generally be preferred when both Po-small and Po-macro were –100 dBm. Further study will determine an OL/TPC algorithm and investigate its system performance. Acknowledgements This work was supported by a grant from the Institute for Information & Communications Technology Promotion (IITP) of the Ministry of Science, ICT and Future Planning (MSIP), Rep. of Korea (R0101-15-224, Development of 5G Mobile Communication Technologies for Hyper-connected Smart Services). Biographies Amir Haider received his BS degree in electronics engineering from International Islamic University, Islamabad, Pakistan in 2012 and his MS degree in electrical engineering from the University of Engineering and Technology, Taxila, Pakistan in 2014. From 2014 to 2015, he served as a lecturer in the Department of Electrical Engineering at COMSATS Institute of Information Technology, Abbottabad, Pakistan. Currently, he is on study leave to pursue his PhD degree at Dongguk University, Seoul, Rep. of Korea. His current research interests are 5G mobile networks, ultradense network deployments, and wireless positioning technologies. Rashmi Sharan Sinha received her B.Tech. degree in electronics and communication engineering from Lala Lajpat Rai Institute of Engineering and Technology, Moga under Punjab Technical University, Jalandhar, India in 2011 and her MTech. degree in electronics and communication engineering from Shaheed Bhagat Singh State Technical Campus, Firozpur under Punjab Technical University, Jalandhar, India in 2015. Since 2015, she has been pursuing a PhD degree with the Division of Electronics and Electrical Engineering, Dongguk University, Seoul, Rep. of Korea. Her main research interests are optimization algorithms and wireless communication systems. Seung-Hoon Hwang received BS, MS, and PhD degrees in electrical engineering from Yonsei University, Seoul, Rep. of Korea in 1992, 1994, and 1999, respectively. From 1999 to 2004, he worked for UMTS standardization at LG Electronics, Rep. of Korea. From 2003 to 2004, he was a Visiting Research Fellow with Prof. Lajos Hanzo at the University of Southampton, U.K. He is a recipient of the British Chevening Scholarship funded by the Foreign and Commonwealth Office, U.K. He is now a Professor in the Division of Electronics and Electrical Engineering at Dongguk University, Seoul, Rep. of Korea. In 2010, he was a Visiting Professor with Prof. John Cioffi at Stanford University, CA, U.S.A. He is a Senior Member of IEEE, an Executive Director for the Korean Institute of Communications and Information Sciences, Korea, and a Vice-chairman for the spectrum committee in the 5G forum, Korea. References 1X. Ge, S. Tu, G. Mao, C.-X. Wang, and T. Han, "5G Ultra-Dense Cellular Networks," IEEE Wirel. Commun., vol. 23, no. 1, Feb. 2016, pp. 72– 79. 2X. Ge, H. Cheng, M. Guizani, and T. Han, "5G Wireless Backhaul Networks: Challenges and Research Advances," IEEE Netw., vol. 28, no. 6, Nov. 2014, pp. 6– 11. 3R. Kwan and C. Leung, "A Survey of Scheduling and Interference Mitigation in LTE," J. Electr. Comput. Eng., vol. 2010, no. 1, Jan. 2010, pp. 1– 10. 4G. Boudreau, J. Panicker, N. Guo, R. Chang, N. Wang, and S. Vrzic, "Interference Coordination and Cancellation for 4G Networks," IEEE Commun. Mag., vol. 47, no. 4, May 2009, pp. 74– 81. 5M. Rahman, H. Yanikomeroglu, and W. Wong, "Interference Avoidance with Dynamic Inter-cell Coordination for Downlink LTE System," Proc. IEEE Wirel. Commun. Netw. Conf., Budapest, Hungary, Apr. 5–8, 2009, pp. 1– 6. 6D. Lopez-Perez, I. Guvenc, G. de la Roche, M. Kountouris, T.Q.S. Quek, and J. Zhang, "Enhanced Intercell Interference Coordination Challenges in Heterogeneous Networks," IEEE Wirel. Commun., vol. 18, no. 3, June 2011, pp. 22– 30. 7A. Simonsson and A. Furuskar, " Uplink Power Control in LTE - Overview and Performance, Subtitle: Principles and Benefits of Utilizing Rather than Compensating for SINR Variations," Proc. IEEE Veh. Tech. Conf., Calgary, Canada, Sept. 21–24, 2008, pp. 1– 5. 8K. Okino, T. Nakayama, C. Yamazaki, H. Sato, and Y. Kusano, " Pico Cell Range Expansion with Interference Mitigation toward LTE-Advanced Heterogeneous Networks," Proc. IEEE Int. Conf. Commun. Workshops, Kyoto, Japan, June 5–9, 2011, pp. 1– 5. 9B. Muhammad, " Closed Loop Power Control for LTE Uplink," M.S. thesis, Dept. Sig. Proc., Blekinge Inst. Tech., Karlskrona, Sweden, 2008. 10 3GPP Std TSG-RAN WG1 #51, R1-074850: Uplink Power Control for E-UTRA – Range and Representation of Po, Jeju, Rep. of Korea, 2007. 11E.R. Cîrstea and S. Ciochină, " LTE Uplink Power Control and Its Impact on System Performance," Proc. Int. Conf. Adaptive Self-Adaptive Syst. Appl., Rome, Italy, Sept. 11–14, 2011, pp. 57– 61. 12P. Koleva et al., " Improved Open Loop Power Control for LTE Uplink," Proc. Int. Conf. Telecommun. Signal Process., Prague, Czech Rep. July 9–11, 2015, pp. 1– 5. 13A.V. Mora, M. Toril, S. Luna-Ramírez, A. Mendo, and S. Pedraza, "Congestion Relief in Subway Areas by Tuning Uplink Power Control in LTE," IEEE Trans. Veh. Technol., vol. 66, no. 7, July 2017, pp. 6489– 6497. 14A. Haider, S.H. Lee, D.I. Kim, H.K. Jwa, and S.H. Hwang, " On Uplink Power Control for Small Cell in LTE," Proc. KICS Winter Conf., Jeongsun, Rep. of Korea, Jan. 7–11, 2016, pp. 427– 428. 15W. Kim, Z. Kaleem, and K. Chang, " UE-Specific Interference-Aware Open-Loop Power Control in 3GPP LTE-A Uplink HetNet," Proc. Int. Conf. Ubiquitous Future Netw., Sapporo, Japan, July 7–10, 2015, pp. 682– 684. 16K. Safjan and C. Rosa, " Open Loop Power Control Parameter Settings Impact on LTE HetNet Uplink Performance," Proc. IEEE Int. Conf. Commun. Workshops (ICC), Budapest, Hungary, June 9–13, 2013, pp. 1134– 1138. 17E. Tejaswi and B. Suresh, "Survey of Power Control Schemes for LTE Uplink," Int. J. Comput. Sci. Inform. Technol., vol. 4, no. 2, Apr. 2013, pp. 369– 373. 18A. Haider, S.H. Lee, S.H. Hwang, D.I. Kim, and J.H. Na, " Uplink Open Loop Power Control for LTE HetNet," Proc. IEEE URSI Asia-Pacific Radio Sci. Conf., Seoul, Rep. of Korea, Aug. 21–25, 2016, pp. 83– 85. 19H. Martikainen, I. Viering, and B. Wegmann, " Dynamic Range Aware LTE Uplink Po Optimization in HetNet," Proc. IEEE Int. Conf. Commun., Kuala Lumpur, Malaysia, May 22–27, 2016, pp. 1– 6. 20J.M. Kelif, M. Coupechoux, and P. Godlewski, "A Fluid Model for Performance Analysis in Cellular Networks," EURASIP J. Wirel. Commun. Netw., vol. 2010, no. 1, Dec. 2010, pp. 1– 11. 21T.D. Novlan, H.S. Dhillon, and J.G. Andrews, "Analytical Modeling of Uplink Cellular Networks," IEEE Trans. Wirel. Commun., vol. 12, no. 6, May 2013, pp. 2669– 2679. 22H.S. Dhillon, R.K. Ganti, and J.G. Andrews, "Modeling Non-uniform UE Distributions in Downlink Cellular Networks," IEEE Wirel. Commun. Lett., vol. 2, no. 3, Apr. 2013, pp. 339– 342. 23M. Coupechoux and J.M. Kelif, " How to Set the Fractional Power Control Compensation Factor in LTE?," Proc. IEEE Sarnoff Symp., Princeton, NJ, USA, May 3–4, 2011, pp. 1– 5. 24J.M. Kelif and M. Coupechoux, " Joint Impact of Pathloss Shadowing and Fast Fading - An Outage Formula for Wireless Networks," Preprint, submitted Jan. 7 2010, Accessed 2017. https://arxiv.org/abs/1001.1110v1. 25J.M. Kelif and M. Coupechoux, " Impact of Topology and Shadowing on the Outage Probability of Cellular Networks," Proc. IEEE Int. Conf. Commun., Dresden, Germany, June 14–18, 2009, pp. 1– 6. 26S. Berger, B. Almeroth, V. Suryaprakash, P. Zanier, I. Viering, and G. Fettweis, "Dynamic Range-Aware Uplink Transmit Power Control in LTE Networks: Establishing an Operational Range for LTE's Open-Loop Transmit Power Control Parameters," IEEE Wirel. Commun. Lett., vol. 3, no. 5, Aug. 2014, pp. 521– 524. Citing Literature Volume40, Issue1Special Issue: 5G Communications and Experimental Trials with Heterogeneous and Agile Mobile networksFebruary 2018Pages 51-60 FiguresReferencesRelatedInformation