IEEEAcCeSSSPECIALSECTION ONRECENTADVANCESIN SOFTWAREDEFINEDNETWORKINGFOR5GNETWORKSReceived July 11, 2015, accepted July 22, 2015, date of publication July 28, 2015, date of current version August 7, 2015.Digital Object Idenrifier 10.1109/ACCESS.2015.2461602ASurveyof5GNetwork:ArchitectureandEmerging TechnologiesAKHILGUPTA,(StudentMember,IEEE),ANDRAKESHKUMARJHA,(SeniorMember,IEEE)School of Electronics and Communication Engineering. Shri Mata Vaishno Devi University, Katra 182320, IndisCorresponding author: A.Gupta (akhilguptal12001@gmail.com)ABSTRACT In the near future, i.e., beyond 4G, some of the prime objectives or demands that need tobe addressed are increased capacity,improved data rate, decreased latency, and better quality of service.To meet these demands, drastic improvements need to be made in cellular network architecture. This paperpresents theresults of adetailed survey on the fifthgeneration (5G)cellular network architecture and someof the key emerging technologies that are helpful in improving the architecture and meeting the demands ofusers.In this detailed survey,the prime focus is on the 5G cellular network architecture,massive multipleinput multiple output technology, and device-to-device communication (D2D). Along with this, some of theemerging technologies that are addressed in this paper include interferencemanagement, spectrum sharingwith cognitive radio, ultra-dense networks, multi-radio access technology association,full duplex radios,millimeter wave solutionsfor 5G cellular networks,and cloudtechnologiesfor 5Gradio access networksandsoftwaredefinednetworks.In thispaper,ageneral probable5Gcellular networkarchitecture isproposedwhich shows thatD2D,small cell access points,network cloud,and theInternet of Things can be a partof5G cellular network architecture.A detailed survey is included regarding current research projects beingconducted in different countries by research groups and institutions that are working on 5G technologies.:INDExTERMS5G,cloud,D2D,massiveMIMO,mm-wave,relay,small-cellLINTRODUCTIONeruption of new applications which will be used in casesforToday and in the recent future, to fulfill the presumptionsmobile connectivity and a resultant exponential growth inand challenges of the near future. thewirelessbased net-network traffic.This paper presents our view on the future ofworks of todaywill haveto advance in various ways.Recentwireless communication for 2020 and beyond. In this paper,technology constituent like high-speed packet access (HSPA)we describe the key challenges that will be encountered byand long-term evolution (LTE)wili be launched as afuture wireless communication whileenabling the networkedsegment of the advancement of current wireless basedsociety.Along with this,sometechnologyroutes thatmaybetechnologies.Nevertheless, auxiliary components may alsotaken to fulfill these challenges [1]constitute future new wireless based technologies,whichThe imagination of ourfuture is a networked society withmay adjunct the evolved technologies.Specimen of theseunbounded access to information and sharing ofdata whichnewtechnologycomponentsaredifferentways of accessingis accessible everywhere and every timefor everyone andspectrum and considerably higher frequency ranges, theeverything.To realize this imagination,newtechnology com-instigation of massive antenna configurations,direct device-ponents need to be examined for the evolution of existingwireless based technologies.Present wireless based techto-devicecommunication,andultra-densedeployments[1]Since its initiation in the late 1970s, mobile wirelessnologies,likethe3rdGenerationPartnershipProject(3GPP)LTE technology, HSPA and Wi-Fi, will be incorporating newcommunicationhascomeacrossfromanalogvoicecallstocurrent modern technologies adept of providing high qual-technology components that will be helping to meet the needsity mobile broadband serviceswith end-userdata rates ofofthefuture.Nevertheless,theremaybecertain scenariosthatseveral megabits per second over wide areas andtens, orcannot be adequately addressed along with the evolution ofeven hundreds,ofmegabits per second locally.Theextensiveongoing existing technologies.Theinstigation of completelyimprovements interms of potentiality of mobilecommunica-newwirelessbasedtechnologieswillcomplementthecurrenttionnetworks,alongwiththeinitiationofnewtypesofmobiletechnologies which are needed for the long term realizationdevices such as smart phones and tablets, have produced anof the networked society [2].2169-3536 e 2015 IEEE. Translations and content mining are permitted for academic research only.1206VOLUME3,2015Personal use is also permitted, but republication/redistribution requires IEEE permissionSeehttp://www.ieee.org/publications_standards/publications/rights/index.htmlformoreinformation
SPECIAL SECTION ON RECENT ADVANCES IN SOFTWARE DEFINED NETWORKING FOR 5G NETWORKS Received July 11, 2015, accepted July 22, 2015, date of publication July 28, 2015, date of current version August 7, 2015. Digital Object Identifier 10.1109/ACCESS.2015.2461602 A Survey of 5G Network: Architecture and Emerging Technologies AKHIL GUPTA, (Student Member, IEEE), AND RAKESH KUMAR JHA, (Senior Member, IEEE) School of Electronics and Communication Engineering, Shri Mata Vaishno Devi University, Katra 182320, India Corresponding author: A. Gupta (akhilgupta112001@gmail.com) ABSTRACT In the near future, i.e., beyond 4G, some of the prime objectives or demands that need to be addressed are increased capacity, improved data rate, decreased latency, and better quality of service. To meet these demands, drastic improvements need to be made in cellular network architecture. This paper presents the results of a detailed survey on the fifth generation (5G) cellular network architecture and some of the key emerging technologies that are helpful in improving the architecture and meeting the demands of users. In this detailed survey, the prime focus is on the 5G cellular network architecture, massive multiple input multiple output technology, and device-to-device communication (D2D). Along with this, some of the emerging technologies that are addressed in this paper include interference management, spectrum sharing with cognitive radio, ultra-dense networks, multi-radio access technology association, full duplex radios, millimeter wave solutions for 5G cellular networks, and cloud technologies for 5G radio access networks and software defined networks. In this paper, a general probable 5G cellular network architecture is proposed, which shows that D2D, small cell access points, network cloud, and the Internet of Things can be a part of 5G cellular network architecture. A detailed survey is included regarding current research projects being conducted in different countries by research groups and institutions that are working on 5G technologies. INDEX TERMS 5G, cloud, D2D, massive MIMO, mm-wave, relay, small-cell. I. INTRODUCTION Today and in the recent future, to fulfill the presumptions and challenges of the near future, the wireless based networks of today will have to advance in various ways. Recent technology constituent like high-speed packet access (HSPA) and long-term evolution (LTE) will be launched as a segment of the advancement of current wireless based technologies. Nevertheless, auxiliary components may also constitute future new wireless based technologies, which may adjunct the evolved technologies. Specimen of these new technology components are different ways of accessing spectrum and considerably higher frequency ranges, the instigation of massive antenna configurations, direct deviceto-device communication, and ultra-dense deployments [1]. Since its initiation in the late 1970s, mobile wireless communication has come across from analog voice calls to current modern technologies adept of providing high quality mobile broadband services with end-user data rates of several megabits per second over wide areas and tens, or even hundreds, of megabits per second locally. The extensive improvements in terms of potentiality of mobile communication networks, along with the initiation of new types of mobile devices such as smart phones and tablets, have produced an eruption of new applications which will be used in cases for mobile connectivity and a resultant exponential growth in network traffic. This paper presents our view on the future of wireless communication for 2020 and beyond. In this paper, we describe the key challenges that will be encountered by future wireless communication while enabling the networked society. Along with this, some technology routes that may be taken to fulfill these challenges [1]. The imagination of our future is a networked society with unbounded access to information and sharing of data which is accessible everywhere and every time for everyone and everything. To realize this imagination, new technology components need to be examined for the evolution of existing wireless based technologies. Present wireless based technologies, like the 3rd Generation Partnership Project (3GPP) LTE technology, HSPA and Wi-Fi, will be incorporating new technology components that will be helping to meet the needs of the future. Nevertheless, there may be certain scenarios that cannot be adequately addressed along with the evolution of ongoing existing technologies. The instigation of completely new wireless based technologies will complement the current technologies which are needed for the long term realization of the networked society [2]. 1206 2169-3536 2015 IEEE. Translations and content mining are permitted for academic research only. Personal use is also permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. VOLUME 3, 2015
IEEEAcceSSA. Gupta, R. K. Jha: Survey of 5G Network: Architecture and Emerging TechnologiesThe remainder of the paper is organized as follows:and withno security,sincevoicecalls were storedandplayedIn Section IL,we present theevolution ofwirelessin radio towers due to which vulnerability of these calls fromtechnologies.Section Ill gives the detailed description ofunwanted eavesdroppingby third party increases [7]the proposed general 5G cellular network architecture.B.2GSection IV comprises of the detailed explanation of theThe 2nd generation was introduced in late 1990's.emerging technologies for 5G wireless networks.We con-Digital technology is used in 2nd generation mobile tele-clude our paper in Section V.A list of current researchprojects based on 5G technologies is shown in the appendix.phones.Global Systems forMobile communications (GSM)was the first 2nd generation system, chiefly used for voiceII.EVOLUTIONOFWIRELESSTECHNOLOGIEScommunication and having a data rate upto64kbpsG.Marconi,an Italianinventor,unlocks thepath of2G mobile handsetbatterylasts longerbecause of the radiorecentdaywireless communicationsbycommunicatingthesignals having low power. It also provides services like Shortletter‘S'alongadistanceof 3Kmintheformof threedotMessage Service (SMS) and e-mail. Vital eminent technolo-Morse code with the help of electromagnetic waves. Aftergies were GSM, Code Division Multiple Access (CDMA),this inception,wireless communications have become anand IS-95 [3], [7].important part of present day society.Since satellite comC. 2.5Gmunication, television and radio transmission has advancedIt generally subscribes a 2nd generation cellular systemto pervasivemobiletelephone,wireless communications hastransformed thestyleinwhichsocietyruns.Theevolutionmerged with General PacketRadio Services (GPRS)andof wireless begins here [2] and is shown in Fig.1. It showsother amenities doesn'tcommonlyendow in 2G or 1Gthe evolvinggenerations of wireless technologies in terms ofnetworks.A 2.5G system generally uses 2G systemdatarate,mobility,coverageandspectralefficiency.Astheframeworks,but it applies packet switching along withwireless technologies are growing,the data rate, mobilitycircuit switching.It can assist data rate up to 144kbps. Themain 2.5Gtechnologies wereGPRS,EnhancedDataRatecoverage and spectral efficiencyincreases.It also showsthat the 1G and 2G technologies use circuit switching whilefor GSM Evolution (EDGE), and Code Division Multiple2.5Gand3Guses bothcircuitandpacketswitching andAccess (CDMA) 2000 [3], [7].the next generations from 3.5G to now i.e. 5G are usingD.3Gpacket switching.Along with these factors, it also differ-The 3rd generation was established in late 200. It impartsentiatebetween licensed spectrumandunlicensed spectrumAll the evolving generations use the licensed spectrum whiletransmission rateupto 2Mbps.Thirdgeneration (3G)the WiFi, Bluetooth and WiMAX are using the unlicensedsystems merge high speed mobile access to services basedon InternetProtocol (IP).Asidefrom transmission ratespectrum.An overviewabout theevolving wirelesstechnologies is below:unconventionalimprovementwasmadeformaintainingOosAdditional amenities like global roaming and improved voiceMobility/Coveragequality made 3G as a remarkablegeneration.The majordisadvantage for 3G handsets is that, they require morepower thanmost2Gmodels.Alongwiththis 3G networkplans are more expensive than 2G [3], [7]. SinceVehicularLicensed Spectrum73G involves the introduction and utilization of WidebandCode Division Multiple Access (WCDMA),UniversalPedestrian00Mobile Telecommunications Systems (UMTS)and CodeBEYONDGANDDivisionMultiple Access(CDMA)2000technologies,theFixedHETEROGENEOUSevolving technologies like High Speed Uplink/DownlinkNETWORKS (5G)PedestrianPacket Access (HSUPA/HSDPA)and Evolution-DataWiFi(802.1)100Optimized (EVDO)has made an intermediate wirelessotoFixedUnlicensed Spectrumgenerationbetween3Gand4Gnamedas3.5Gwith improvedData Ratedata rate of 5-30 Mbps [3]FIGURE 1.Evolution of wireless technologies.E.3.75GA.1GLong-TermEvolution technology (LTE)andFixedThe 1st generation was announced in initial 1980's.WorldwideInteroperabilityforMicrowaveAccess (WIMAX)It has a data rate up to 2.4kbps.Major subscribers wereis thefuture of mobiledata services.LTE andFixed WIMAXAdvanced Mobile Phone System (AMPS), Nordic Mobilehas thepotential to supplement the capacity of the networkTelephone(NMT),and Total Access Communicationand provides a substantial number of users the facilitytoSystem (TACS).Ithas a lot of disadvantages like belowaccess a broad range of high speed services like on demandpar capacity,reckless handoff, inferior voice associations,video, peer to peer file sharing and composite Web services.VOLUME 3, 20151207
A. Gupta, R. K. Jha: Survey of 5G Network: Architecture and Emerging Technologies The remainder of the paper is organized as follows: In Section II, we present the evolution of wireless technologies. Section III gives the detailed description of the proposed general 5G cellular network architecture. Section IV comprises of the detailed explanation of the emerging technologies for 5G wireless networks. We conclude our paper in Section V. A list of current research projects based on 5G technologies is shown in the appendix. II. EVOLUTION OF WIRELESS TECHNOLOGIES G. Marconi, an Italian inventor, unlocks the path of recent day wireless communications by communicating the letter ‘S’ along a distance of 3Km in the form of three dot Morse code with the help of electromagnetic waves. After this inception, wireless communications have become an important part of present day society. Since satellite communication, television and radio transmission has advanced to pervasive mobile telephone, wireless communications has transformed the style in which society runs. The evolution of wireless begins here [2] and is shown in Fig. 1. It shows the evolving generations of wireless technologies in terms of data rate, mobility, coverage and spectral efficiency. As the wireless technologies are growing, the data rate, mobility, coverage and spectral efficiency increases. It also shows that the 1G and 2G technologies use circuit switching while 2.5G and 3G uses both circuit and packet switching and the next generations from 3.5G to now i.e. 5G are using packet switching. Along with these factors, it also differentiate between licensed spectrum and unlicensed spectrum. All the evolving generations use the licensed spectrum while the WiFi, Bluetooth and WiMAX are using the unlicensed spectrum. An overview about the evolving wireless technologies is below: FIGURE 1. Evolution of wireless technologies. A. 1G The 1st generation was announced in initial 1980’s. It has a data rate up to 2.4kbps. Major subscribers were Advanced Mobile Phone System (AMPS), Nordic Mobile Telephone (NMT), and Total Access Communication System (TACS). It has a lot of disadvantages like below par capacity, reckless handoff, inferior voice associations, and with no security, since voice calls were stored and played in radio towers due to which vulnerability of these calls from unwanted eavesdropping by third party increases [7]. B. 2G The 2nd generation was introduced in late 1990’s. Digital technology is used in 2nd generation mobile telephones. Global Systems for Mobile communications (GSM) was the first 2nd generation system, chiefly used for voice communication and having a data rate up to 64kbps. 2G mobile handset battery lasts longer because of the radio signals having low power. It also provides services like Short Message Service (SMS) and e-mail. Vital eminent technologies were GSM, Code Division Multiple Access (CDMA), and IS-95 [3], [7]. C. 2.5G It generally subscribes a 2nd generation cellular system merged with General Packet Radio Services (GPRS) and other amenities doesn’t commonly endow in 2G or 1G networks. A 2.5G system generally uses 2G system frameworks, but it applies packet switching along with circuit switching. It can assist data rate up to 144kbps. The main 2.5G technologies were GPRS, Enhanced Data Rate for GSM Evolution (EDGE), and Code Division Multiple Access (CDMA) 2000 [3], [7]. D. 3G The 3rd generation was established in late 2000. It imparts transmission rate up to 2Mbps. Third generation (3G) systems merge high speed mobile access to services based on Internet Protocol (IP). Aside from transmission rate, unconventional improvement was made for maintaining QoS. Additional amenities like global roaming and improved voice quality made 3G as a remarkable generation. The major disadvantage for 3G handsets is that, they require more power than most 2G models. Along with this 3G network plans are more expensive than 2G [3], [7]. Since 3G involves the introduction and utilization of Wideband Code Division Multiple Access (WCDMA), Universal Mobile Telecommunications Systems (UMTS) and Code Division Multiple Access (CDMA) 2000 technologies, the evolving technologies like High Speed Uplink/Downlink Packet Access (HSUPA/HSDPA) and Evolution-Data Optimized (EVDO) has made an intermediate wireless generation between 3G and 4G named as 3.5G with improved data rate of 5-30 Mbps [3]. E. 3.75G Long-Term Evolution technology (LTE) and Fixed Worldwide Interoperability for Microwave Access (WIMAX) is the future of mobile data services. LTE and Fixed WIMAX has the potential to supplement the capacity of the network and provides a substantial number of users the facility to access a broad range of high speed services like on demand video, peer to peer file sharing and composite Web services. VOLUME 3, 2015 1207
IEEEAcceSSA. Gupta, R. K. Jha: Survey of 5G Network: Architecture and Emerging TechnologiesAlong with this, a supplementary spectrum is accessiblethewirelesssetupwhichhadcomeaboutfrom1Gto4Gwhich accredit operators manage their network very compli-Alternatively, there could be only the addition of an appli-cation or amelioration done at the fundamental network toantly and offersbetter coveragewith improved performanceforless cost [4]H7].please user requirements.This will provoke the packageproviders to drift for a 5G network as early as 4G is com-F.4Gmercially set up [8]. To meet the demands of the user and4G is generallyreferred as the descendant of the3G and 2Gto overcome the challenges that has been put forward in thestandards.3rd Generation Partnership Project (3GPP)5G system, a drastic change in the strategy of designingis presently standardizing Long Term Evolution (LTE)the 5G wireless cellular architecture is needed. A generalAdvanced asforthcoming4G standard along withMobileobservation of the researchers has shown in [14] that most ofWorldwideInteroperabilityforMicrowaveAccess(WIMAX)the wireless users stayinsideforapproximately80percent ofA4G system improves the prevailingcommunicationtime and outsidefor approximately20 percent of the time.In present wireless cellular architecture, for a mobile usernetworks by imparting acompleteandreliable solution basedon IP.Amenities like voice,data and multimedia will beto communicate whether inside or outside, an outside basestation present in the middle of a cell helps incommunication.imparted to subscribers on every time and everywhere basisand at quite higher data rates as related to earlier generations.So for inside usersto communicate with the outside baseApplicationsthat are beingmadetouse a 4Gnetwork arestation, the signals will have to travel through the walls ofMultimedia Messaging Service (MMS),Digital Videothe indoors, and this will result in very high penetration lossBroadcasting (DVB), and video chat, High Definition TVwhichcorrespondinglycosts with reduced spectral efficiency,data rate,and energyefficiency ofwireless communications.content and mobile TV [2], [4]H6].To overcome this challenge, a new idea or designing tech-G.5Gnique that has come in to existence for scheming the5G cellular architecture is to distinct outside and insideWith an exponential increase in the demand of the userssetups [8].With this designing technique, the penetration loss4G will now be easily replaced with 5G withanthrough the walls of the building will be slightly reduced.advanced access technology named Beam Division MultipleThis idea will be supported with the help of massive MIMOAccess (BDMA)and Non-and quasi-orthogonal or FilterBank multi carrier (FBMC) multiple access. The concepttechnology [15], in which geographically dispersed arrayof antenna's are deployed which have tens or hundreds ofbehind BDMAtechniqueisexplainedby considering the caseantennaunits.SincepresentMIMOsystemsareusingeitherofthebasestationcommunicatingwiththemobilestations.twoorfour antennas,buttheideaofmassiveMIMO systemsIn this communication,an orthogonal beamisallocated toeachmobile station and BDMAtechnique will divide thathas come up with the idea of utilizing theadvantages of largearray antenna elements in terms of huge capacity gains.antenna beam accordingto locations of themobile stationsTo build or construct a largemassive MIMO network,for giving multiple accesses to themobile stations, whichfirstly the outside base stations will be fitted with largecorrespondingly increase the capacity of the system [8].An idea to shift towards 5G is based on current drifts,it isantenna arrays and among them some are dispersed aroundthe hexagonal cell and linked to the base station throughcommonly assumed that5G cellularnetworks mustaddressoptical fibercables,aidedwithmassiveMIMOtechnologiessix challenges that are not effectively addressed by 4G ie.higher capacity, higher data rate, lower End to End latency.The mobile users present outside are usually fitted with acertain number of antenna units but with cooperation a largemassive device connectivity,reduced cost and consistentQuality of Experience provisioning [22], [23]. Thesevirtualantennaarraycanbeconstructed,whichtogetherwithantenna arrays of base station formvirtual massive MIMOchallenges are concisely shown in Fig. 2 along withlinks.Secondly,every building will be installed with largesome potential facilitators to address them. An overviewantenna arraysfrom outside,tocommunicate with outdoorof the challenges,facilitators, and corresponding designbase stations with the help of line of sight componentsfundamentals for 5G is shown in Fig.2 [20].RecentlyThe wireless access points inside the building are connectedintroduced IEEE 802.11ac,802.11ad and 802.11af standardswith the large antenna arrays through cables for communi-are very helpful and act as a building blocks in the roadcating with indoor users. This will significantly improvestowards5G[9]H13].Thetechnicalcomparisonbetween thesethe energy efficiency,cell average throughput, data rate, andstandards is shown in table 1 and the detailed comparison ofspectral efficiency of the cellular system but at the expensewireless generations is shown intable2of increased infrastructure cost.With the introduction ofIIL5GCELLULARNETWORKARCHITECTUREsuch an architecture, the inside users will only have toTo contemplate5G network in the market now,it is evidentconnect or communicate with inside wireless access pointsthat the multiple access techniques in the network arewhile larger antenna arays remained installed outside thealmost at a still and requires sudden improvement.Currentbuildings[8].For indoor communication,certain technolo-technologies like OFDMA will work at least for nextgies like WiFi, Small cell, ultra wideband,millimeter wave50 years. Moreover, there is no need to have a change incommunications [16], and visible light communications [17]1208VOLUME 3,2015
A. Gupta, R. K. Jha: Survey of 5G Network: Architecture and Emerging Technologies Along with this, a supplementary spectrum is accessible which accredit operators manage their network very compliantly and offers better coverage with improved performance for less cost [4]–[7]. F. 4G 4G is generally referred as the descendant of the 3G and 2G standards. 3rd Generation Partnership Project (3GPP) is presently standardizing Long Term Evolution (LTE) Advanced as forthcoming 4G standard along with Mobile Worldwide Interoperability for Microwave Access (WIMAX). A 4G system improves the prevailing communication networks by imparting a complete and reliable solution based on IP. Amenities like voice, data and multimedia will be imparted to subscribers on every time and everywhere basis and at quite higher data rates as related to earlier generations. Applications that are being made to use a 4G network are Multimedia Messaging Service (MMS), Digital Video Broadcasting (DVB), and video chat, High Definition TV content and mobile TV [2], [4]–[6]. G. 5G With an exponential increase in the demand of the users, 4G will now be easily replaced with 5G with an advanced access technology named Beam Division Multiple Access (BDMA) and Non- and quasi-orthogonal or Filter Bank multi carrier (FBMC) multiple access. The concept behind BDMA technique is explained by considering the case of the base station communicating with the mobile stations. In this communication, an orthogonal beam is allocated to each mobile station and BDMA technique will divide that antenna beam according to locations of the mobile stations for giving multiple accesses to the mobile stations, which correspondingly increase the capacity of the system [8]. An idea to shift towards 5G is based on current drifts, it is commonly assumed that 5G cellular networks must address six challenges that are not effectively addressed by 4G i.e. higher capacity, higher data rate, lower End to End latency, massive device connectivity, reduced cost and consistent Quality of Experience provisioning [22], [23]. These challenges are concisely shown in Fig. 2 along with some potential facilitators to address them. An overview of the challenges, facilitators, and corresponding design fundamentals for 5G is shown in Fig. 2 [20]. Recently introduced IEEE 802.11ac, 802.11ad and 802.11af standards are very helpful and act as a building blocks in the road towards 5G [9]–[13]. The technical comparison between these standards is shown in table 1 and the detailed comparison of wireless generations is shown in table 2. III. 5G CELLULAR NETWORK ARCHITECTURE To contemplate 5G network in the market now, it is evident that the multiple access techniques in the network are almost at a still and requires sudden improvement. Current technologies like OFDMA will work at least for next 50 years. Moreover, there is no need to have a change in the wireless setup which had come about from 1G to 4G. Alternatively, there could be only the addition of an application or amelioration done at the fundamental network to please user requirements. This will provoke the package providers to drift for a 5G network as early as 4G is commercially set up [8]. To meet the demands of the user and to overcome the challenges that has been put forward in the 5G system, a drastic change in the strategy of designing the 5G wireless cellular architecture is needed. A general observation of the researchers has shown in [14] that most of the wireless users stay inside for approximately 80 percent of time and outside for approximately 20 percent of the time. In present wireless cellular architecture, for a mobile user to communicate whether inside or outside, an outside base station present in the middle of a cell helps in communication. So for inside users to communicate with the outside base station, the signals will have to travel through the walls of the indoors, and this will result in very high penetration loss, which correspondingly costs with reduced spectral efficiency, data rate, and energy efficiency of wireless communications. To overcome this challenge, a new idea or designing technique that has come in to existence for scheming the 5G cellular architecture is to distinct outside and inside setups [8]. With this designing technique, the penetration loss through the walls of the building will be slightly reduced. This idea will be supported with the help of massive MIMO technology [15], in which geographically dispersed array of antenna’s are deployed which have tens or hundreds of antenna units. Since present MIMO systems are using either two or four antennas, but the idea of massive MIMO systems has come up with the idea of utilizing the advantages of large array antenna elements in terms of huge capacity gains. To build or construct a large massive MIMO network, firstly the outside base stations will be fitted with large antenna arrays and among them some are dispersed around the hexagonal cell and linked to the base station through optical fiber cables, aided with massive MIMO technologies. The mobile users present outside are usually fitted with a certain number of antenna units but with cooperation a large virtual antenna array can be constructed, which together with antenna arrays of base station form virtual massive MIMO links. Secondly, every building will be installed with large antenna arrays from outside, to communicate with outdoor base stations with the help of line of sight components. The wireless access points inside the building are connected with the large antenna arrays through cables for communicating with indoor users. This will significantly improves the energy efficiency, cell average throughput, data rate, and spectral efficiency of the cellular system but at the expense of increased infrastructure cost. With the introduction of such an architecture, the inside users will only have to connect or communicate with inside wireless access points while larger antenna arrays remained installed outside the buildings [8]. For indoor communication, certain technologies like WiFi, Small cell, ultra wideband, millimeter wave communications [16], and visible light communications [17] 1208 VOLUME 3, 2015
IEEEAcceSSA. Gupta, R. K. Jha: Survey of 5G Network: Architecture and Emerging TechnologiesFacilitators to address challenges5GdesignfundamentalsChallengesSpectrumUse high freguencies andotherspectrumoptionslikeMassive MIMOpooling and aggregation.NewairinterfacesandCapacityNewairinterfacemultiple access schemes candesignedprovidebe1Ox1000Allopticaloptimized high frequencies>70%indo0rnetworkslatencyandmassiveconnectivitySmall cellsData RateOpticaltransmission andswitchingwhereverpossiblex10-100Local offloadBring communicatingContent DeliveringEndtoEnd latencyendpoints closertogetherNetwork(CDN)Addressandcoverage<5msControl/User-planecapacity separatelysplitMassive number ofSoftware basedMinimizenumberOconnectionsapproachesnetworklayersandpoOmuchesourcesasUserdeploymentpossible using cloud.x10-100modelsMinimize functionalitieseaccessSimpleCostperformedbyaccesspoints.pointsEnergyefficientSustainablehardwareMaximize energy efficiencyEnergyOualityofacrossallnetworkentitiesmanagementExperience(QoE)techniquesSelf OrganizingConsistentUseanintelligentagenttoNetworks(SON)manage OoE,routingmobilityand resourceTrafficallocationmanagementBig data-drivennetworkintelligenceFIGURE 2. 5G challenge, facilitators, and design fundamental [20].areuseful for small rangecommunications having largedataconventionallyused for cellular communications.But it isrates.Buttechnologies like millimeter wave and visible lightnot an efficient idea to use these high frequency waves forcommunicationareutilizinghigherfrequencieswhicharenotoutsideand longdistanceapplicationsbecausethesewaves1209VOLUME 3, 2015
A. Gupta, R. K. Jha: Survey of 5G Network: Architecture and Emerging Technologies FIGURE 2. 5G challenge, facilitators, and design fundamental [20]. are useful for small range communications having large data rates. But technologies like millimeter wave and visible light communication are utilizing higher frequencies which are not conventionally used for cellular communications. But it is not an efficient idea to use these high frequency waves for outside and long distance applications because these waves VOLUME 3, 2015 1209
IEEEAcceSSA. Gupta, R. K. Jha: Survey of 5G Network: Architecture and Emerging TechnologiesTABLE 1.Technical comparison between recent 802.11 standards.Technical Specifications802.11an802.11ac802.11ad802.11af2.4,4.9, 5GHz5GHz60 GHzFrequency0.47-0.71 GHzModulation schemeOFDMOFDMOFDM, single carrier,OFDMlow-power singlecarrier20,40 MHz5,10, 20, 40Channel bandwidth20, 40, 80 MHz (160 MHz optional)2 GHzMHzUp to 150 Mbps (1xl, 40 MHz)Up to 433 Mbps (IxI, 80 MHz)4.6 Gbps54MbpsNominal data rate, single streamUp to 867 Mbps (1x1. 160 MHz)Up to 600 Mbps (4x4, 40 MHz)Up to 1.73 Gbps (4x4, 80 MHz)7 GbpsAggregate nominal data rate,multiple streamsUp to 3.47 Gbps (4x4, 160 MHz)Spectral Efficiency21.665 bps/Hz (4x4, 80 MHz)NA15 bps/Hz (4x4, 40 MHz)1 bps/Hz (2GHz)EIRP22-29dBm1-10dBm22-36 dBm16-20 dBmRange12-70 m indoor12-35 m indoor60 m indoor, 100m<100m indooroutdoor<5kmoutdoorYYAYThrough WallsYYNon-Line-of-Sight4YYWorld-Wide AvailabilityYY (Limited in china)will not infiltrate from dense materials efficiently and canControl plane, respectively. Special network functionality aseasily be dispersed by rain droplets, gases, and flora. Though,a service (XaaS)will provide service as per need, resourcemillimeterwaves andvisiblelightcommunicationstechnolo-pooling is one of the examples.Xaas is the connectiongies can enhance the transmission data rate for indoor setupsbetween aradionetwork and a networkcloud [20].The5Gcellularnetwork architecture is explainedbecausethey have come upwithlarge bandwidth.Alongwith the introduction of new spectrum,which is not beingin [8] and [20].It has equal importance in terms of frontconventionally usedfor wireless communication,thereis oneend and backhaul network respectively. In this paper, amore method to solve the spectrum shortage problem bygeneral 5G cellular network architecture has been proposedimprovingthe spectrum utilization of current radio spectraas shown in Fig. 3. It describes the interconnectivitythrough cognitive radio (CR) networks [18].among the different emerging technologies like MassiveSince the 5G cellular architecture is heterogeneous, so itMIMO network,Cognitive Radio network,mobile andmust include macrocells,microcells, small cells,and relays.static small-cell networks.This proposed architecture alsoAmobilesmall cell concept is an integral part of 5G wirelessexplains the role of network function virtualization (NFV)cellular networkand partially comprisesof mobilerelayandcloud in the 5G cellular network architecture.The conceptsmall cell concepts [19]. It is being introduced to put upofDevicetoDevice(D2D)communication,small cellaccesshigh mobility users,which are inside the automobiles andpoints and Internet of things (loT)has alsobeen incorporatedhigh speedtrains.Mobile small cells arepositioned insidethein this proposed 5G cellular network architecture. In general,moving automobiles to communicate with the users insidethis proposed 5G cellular network architecture mayprovidethe automobile, while the massive MIMO unit consistingagood platformforfuture5G standardization network.of large antennaarrays is placed outsidethe automobiletoBut there are several issues that need to be addressed incommunicate with the outside base station.According toorder to realize the wireless network architecture in partic-user's opinion, a mobile small cell is realized as a regularular, and 5G networks in general. Some of these issues aresummarized in Table. 3 [20].base station and itsallied users are all observed asa singleunit to the base station which proves the above idea ofIV.EMERGINGTECHNOLOGIESFORsplitting indoor and outdoor setups.Mobile small cellusers [19] have a high data rate for data rate services with5GWIRELESS NETWORKSconsiderably reduced signaling overhead, as shown in [8]It is expected that mobile and wireless traffic volume willAs the 5G wireless cellular network architecture consistsincrease a thousand-fold over the next decade which willof only two logical layers: a radio network and a networkbe driven by the expected 50 billion connected devices con-cloud.Different types of componentsperforming differentnected to the cloud by2020 and all need to access and sharefunctions are constituting theradio network.The networkdata, anywhere and anytime.With a rapid increase in the numfunction virtualization (NFV) cloud consists of a User planeber of connected devices,some challengesappear which willentity (UPE)and a Control plane entity (CPE)that per-be responded by increasing capacity and by improving energyform higher layer functionalities related to the User andefficiency,costandspectrumutilizationas well as providing1210VOLUME 3,2015
A. Gupta, R. K. Jha: Survey of 5G Network: Architecture and Emerging Technologies TABLE 1. Technical comparison between recent 802.11 standards. will not infiltrate from dense materials efficiently and can easily be dispersed by rain droplets, gases, and flora. Though, millimeter waves and visible light communications technologies can enhance the transmission data rate for indoor setups because they have come up with large bandwidth. Along with the introduction of new spectrum, which is not being conventionally used for wireless communication, there is one more method to solve the spectrum shortage problem by improving the spectrum utilization of current radio spectra through cognitive radio (CR) networks [18]. Since the 5G cellular architecture is heterogeneous, so it must include macrocells, microcells, small cells, and relays. A mobile small cell concept is an integral part of 5G wireless cellular network and partially comprises of mobile relay and small cell concepts [19]. It is being introduced to put up high mobility users, which are inside the automobiles and high speed trains. Mobile small cells are positioned inside the moving automobiles to communicate with the users inside the automobile, while the massive MIMO unit consisting of large antenna arrays is placed outside the automobile to communicate with the outside base station. According to user’s opinion, a mobile small cell is realized as a regular base station and its allied users are all observed as a single unit to the base station which proves the above idea of splitting indoor and outdoor setups. Mobile small cell users [19] have a high data rate for data rate services with considerably reduced signaling overhead, as shown in [8]. As the 5G wireless cellular network architecture consists of only two logical layers: a radio network and a network cloud. Different types of components performing different functions are constituting the radio network. The network function virtualization (NFV) cloud consists of a User plane entity (UPE) and a Control plane entity (CPE) that perform higher layer functionalities related to the User and Control plane, respectively. Special network functionality as a service (XaaS) will provide service as per need, resource pooling is one of the examples. XaaS is the connection between a radio network and a network cloud [20]. The 5G cellular network architecture is explained in [8] and [20]. It has equal importance in terms of front end and backhaul network respectively. In this paper, a general 5G cellular network architecture has been proposed as shown in Fig. 3. It describes the interconnectivity among the different emerging technologies like Massive MIMO network, Cognitive Radio network, mobile and static small-cell networks. This proposed architecture also explains the role of network function virtualization (NFV) cloud in the 5G cellular network architecture. The concept of Device to Device (D2D) communication, small cell access points and Internet of things (IoT) has also been incorporated in this proposed 5G cellular network architecture. In general, this proposed 5G cellular network architecture may provide a good platform for future 5G standardization network. But there are several issues that need to be addressed in order to realize the wireless network architecture in particular, and 5G networks in general. Some of these issues are summarized in Table. 3 [20]. IV. EMERGING TECHNOLOGIES FOR 5G WIRELESS NETWORKS It is expected that mobile and wireless traffic volume will increase a thousand-fold over the next decade which will be driven by the expected 50 billion connected devices connected to the cloud by 2020 and all need to access and share data, anywhere and anytime. With a rapid increase in the number of connected devices, some challenges appear which will be responded by increasing capacity and by improving energy efficiency, cost and spectrum utilization as well as providing 1210 VOLUME 3, 2015