Analysis of Power Density in LTE Femtocells

International Journal of Advanced Resea search in Technology, Engineering and science (A Bim imonthly Open Access Online Journal) Volum olume1, Issue2, Sept-Oct, 2014.ISSN:2349-7173(Online line) Analysis of Pow ower Density in LTE Fe Femtocells Inderjit Sharma1, Ritu Gupta2 ____________________________________ _______________ Abstract- LTE Network is a high speed eed Network but as compare with other Networks there aree places p in Network where there is less coverage or no covera verage. Therefore to provide services in those areas, there is need nee of a technology which can fill the gap. This is donee with w the help of Femtocells. A Femtocell use a very low power po of about 0.1 watt but as the number of Femtocells in an area increases its transmission power also increases. Wee kknow that cellular network are based on radio radiation and an Femtocells are deployed very near to human environmen ent. Therefore, it is very important to take special care re while deploying Femtoells. ____________________________________ _______________ Keywords:LTE,Femtocell, Macrocell, Pow ower Transmission, Power Consumption _______________ ____________________________________ I. INTRODUCTION Today almost everyone uses data servicess with w voice services which demands higher data rates in both oth directions. This demand enforced cellular communities to improve network design and develop new technologies. With ith these demands in mind communities like 3GPP introd roduced LTE and WCDMA.LTE is most promising technolog ogy used today. LTE uses OFDMA (Orthogonal Frequency Division D Multiple Access) to achieve higher data rates. But as we know there are some areas wher here network cannot provide coverage or network quality is low w llike at cell edge or with in building there is need of a technolog ogy which can fulfill required demand. Today most of traffic is produced through indoor devices like smart phones and tablet lets and deployment of macro base station is costly method forr pproviding coverage and quality. Therefore to deal with thes hese issues cellular communities introduced small base stations sta known as Femtocells. Femtocells are low cost, short rt range, low power base stations. They used a transmission ppower of 100 mill watts (0.1 Watt). Femtocell uses the samee ffrequency which is used by macro stations. ____________________________________ _______________ First Author Name: Inderjit Sharma, Departmentt of o Computer Science & Engineering, HCTM Technical Campus, Kaithal, India dia Second Author Name: Ritu Gupta, Department of Computer Science & Engineering, HCTM Technical Campus, Kaithal, India dia ____________________________________ _______________ All Rights Reserved © 2014 IJARTES Femtocells are deployed byy network operators in indoor environment to improve the qua uality of service. Femtocell uses a broadband or DSL connectio ction to connect to network via Internet. By using Femtocells network ne operators deploy a low cost network and improve their th network. Deployment of Femtocells also offloads traffic fic form the main network too. Deployment of Femtocells also lso provides users a high speed Network services in the indoo oor environments. Deployment provides a better voice qualityy there th is also no need to transmit high power since UE are locat cated near to Femtocells. It also improves the quality of multime media services. II. NETWORK ARCH CHITECTURE OF LTE FEMTO TOCELL In a LTE Femtocell Network rk UE is connected to HeNB (Home eNode). HeNB is like lik small base station which broadcast signals in required red coverage area. HeNB is connected to core network via v a broadband connection. Broadband connects UE too core network via Internet. Therefore for identification of Femtocells there is a HeNB Gateway which provides secu curity to core network. HeNB Gateway restricts the unauth uthorized access to network. Femtocell uses different interfac faces for its functioning too. Figure 1. LTE Femt mtocell Architecture III. FEMTOCELL N NETWORK ISSUES Femtocells are low cost metho hod for providing coverage and quality of services to indoor use sers. But as Femtocells also uses the same frequencies whichh are a used by traditional base stations and we known thatt frequency fr spectrum is limited therefore we use frequency re reuse, cell splitting and other techniques to manage this frequ quency spectrum. But with these solutions still there are some issu issues too. • Inferences issues: - As wee know k that Femtocells uses the same frequencies that are usedd bby other network base stations Visit: www.ijartes.org Page 3 International Journal of Advanced Resea search in Technology, Engineering and science (A Bim imonthly Open Access Online Journal) Volum olume1, Issue2, Sept-Oct, 2014.ISSN:2349-7173(Online line) of network operator. This frequency reuse reu can introduce interference between Femtocells and mac acrocell or between Femtocells. Therefore it is required to plan an Femtocells within macro station carefully. • Spectrum issues: - Frequency spectrum m is scarce resource and every operator has limited frequency spectrum. sp Therefore the deployment of large number of Femtoce ocells it’s required to plan spectrum carefully. • Regularity issues: - Femtocells uses a licensed spectrum of a network operator therefore for Femtoc tocells deployment it needs regularity approvals. Regularity approvals app vary from country to country rules and laws. • Health issues: - One of biggest issuee with w Femtocells is that they are deployed nearer to users and ev everyone knows that base stations operate on the basics of Radio dio radiations. These radiations can cause health problem to users. rs. IV.EXPERIMENTAL SETUP UP We used NS-3 for our analysis of power er transmission and consumption. We used different numberr of parameters for Femtocells deployment in our scenario. Fir First we set an area for macro base station and its parameters. rs. After that we set scenario for our experiment. We used different dif number of 500 Home UE Home Intersite H 1 Distance Enb Rat atio (Meter) Area margin 0.5 Macro Enb nb Tx 33 factor Power (Db Dbm) Number of 1 Home Enb nb Tx 20 Macro Power (Db Dbm) Enbsites Number of 1 Macro Enb nb Dl 100 macro Earfcn fcn EnbsitesX Macro UE 0.0001 Home Enb nb Dl 100 density Earfcn fcn Number of Variable Macro Enb En 25 blocks Bandwid idth Number of Variable HomeEn Enb 25 apartments Bandwid idth Number of Variable Number er of Variable floors Home U Ues Home Enb 0.5 Number er of Variable Activation Macro UEs U ratio apartments, rooms and floors in building ng to find out total number of Femtocells deployed. By va varying number of Femtocells we find out their effect on power er transmission Table1:parameter list All Rights Reserved © 2014 IJARTES and power consumption. Wee did this because number of Femtocells deployed in a buildin lding depends upon these factors. We used a deployment ratio off 0.2 0 and activation ratio of 0.5. Number of Femtocells = roun und (4* number of apartments * number of blocks * num umber of floors * Femtocell deployment ratio * Femtocell ll aactivation ratio) We set a bandwidth (100) forr Macrocell M and Femtocells and transmission power used by Mac acrocell (33 db) and Femtocells (20 db). We used a Macro UE E Density of (0.0001) which is how many number of UEs per square meter in Macro cells and Home Ues Home Enb Rat atio of (1) which is number of Ues on average in Femtocells. Femtocells are distributedd randomly in simulation environment. We used a thres reshold value of 204 which is number of Femtocells allowed ed in LTE Network. Femtocells use a low power of (0.1 watt) t) 1100 mill watt. We used a 99.5 mill watt for power transmission ion up to threshold level (99.5 * number of Femtocells). Powe wer consumed by a Femtocell transceiver is 1.8 watt and con onsumed power is also increase linearly with increase in no of Femtocells (1.8 * number of Femtocells). Figure 2. Simulated ted environment V.RESULT T ANALYSIS A From the simulated environmen ent we find out two results, one for power transmission and othe ther for power consumption. We find that for each Femtocell ell there is a 99.5 db power transmitted and up to 204 (thresh eshold) there is linear increase in power transmitted. Threshold is number of Femtocells which can be deployed in LTE netw etwork. But as the number of Femtocells excised threshold old level power transmitted Visit: www.ijartes.org Page 4 International Journal of Advanced Research in Technology, Engineering and science (A Bimonthly Open Access Online Journal) Volume1, Issue2, Sept-Oct, 2014.ISSN:2349-7173(Online) increases almost 1/2 % for each number of deployed Femtocells above threshold. increase in power consumed by Femtocells. Powers consumed by Femtocells are linear for each deployed Femtocell. Up to threshold level 204 (Power transmission =99.5 * number of Femtocells) VI.CONCLUSION From the experimental study of this work we find that LTE has a threshold limit on number of Femtocells and power transmitted required for a single Femtocell is 99.5 db and power consumed by Femtocell is 1.8. Form the power transmission graph we find that power transmitted by Femtocells are linear up to threshold limit and after threshold limit there is sharp increase in power transmitted per Femtocell but power consumed by Femtocells are linear. This increase in power transmitted can produce interference between macrocell UEs and Femtocells UEs or between one Femtocell UEs and other Femtocell UEs. This experiment also introduces the possibility of health concerns which can be introduced due to increase in power transmitted as increased power transmitted can break the regularity laws for deployments of Femtocells. Figure 3. Power Transmission Graph Power transmission graph shows that up to 204 each Femtocell uses a 99.5db transmit power but as number of Femtocells increases 204 there is increase in transmit power too. After threshold level (Power transmission = 99.5 * threshold (204) + (149.25 * (number of Femtocells – threshold)) REFERENCES [1] Chandrasekhar, W. and Andrews, J. G. (The University of Texas at Austin); Gatherer (Texas Instruments), Femtocell Networks: A Survey; IEEE Communications Magazine, September 2008. [2] Chang Seup Kim, Bum-Gon Choi, Ju Yong Lee, Tae-Jin Lee,Hyunseung Choo, and Min Young Chung “Femtocell Deployment to Minimize Performance Degradation in Mobile WiMAX Systems” ICCSA 2010. [3] ITU, “The World in 2014: ICT Facts and Figures,” tech. rep, ITU, 2014. [4] Jia Liu, Member, IEEE, Tianyou Kou, Qian Chen, and Hanif D. Sherali “Femtocell Base Station Deployment in Commercial Buildings: A Global Optimization Approach” IEEE 2012. [5] M. Deruyck, W. Vereecken, W. Joseph, B. Lannoo, M. Pickavet, and L. Martens “REDUCING THE POWER CONSUMPTION IN WIRELESS ACCESS NETWORKS: OVERVIEW AND RECOMMENDATIONS” Progress in Electromagnetics Research, Vol. 132, 255-274, 2012. [6] O.A Akinlabi, B.S. Paul, M. Joseph and H.C. Ferreira “A Review of Femtocell” International MultiConference of Engineers and Computer Scientists 2014 Vol II, IMECS 2014, March 12 - 14, 2014, Hong Kong [7] [7]Parag Kulkarni, Woon Hau Chin, Tim Farnham “Radio Resource Management Considerations for LTE Femto Cells” ACM SIGCOMM Computer Communication Review, Volume 40, Number 1, January 2010. [8] Seema M Hanchate, Sulakshana Borsune, Shravani Shahapure “3GPP LTE FEMTOCELL – PROS & CONS” INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE & ADVANCED TECHNOLOGY Volume-2, Issue-6, 1596 – 1602, 2012. [9] Small Cell Forum, HeNB (LTE Femto) Network Architecture, Release 1, Document 025.01.01, May 2011. [10] Yoram Haddad, Yisroel Mirsky “Power Efficient Femtocell Distribution Strategies”, 2011. Figure 4. Power Consumption Graph In Power consumption graph we find that there is no extra power consumed by a Femtocell transceiver. It uses 1.8 watt up to threshold level and after threshold level there is no All Rights Reserved © 2014 IJARTES Visit: www.ijartes.org Page 5