| More than a several decades passed since wireless mobile telecommunications were introduced with the first generation,which particularly mainly consist of voice systems.During a recent couple of years,world witnessed sequential,but steady evolution of wireless communications towards following generations.Implementation of diverse digital modulations,efficient frequency reuse,predominance of packet-based Internet and consecutive advancement in physical layer technologies,for example,OFDMA,WCDMA,MIMO,HARQ invested in success of technological evolution.While popularity of smart is gradually growing,every IP-based 4G network device became a part of mundane life.Thus,complex of user-oriented applications,like video streaming,online gaming,health care services provide wide business perspectives to rise revenue.Indeed,there is no man who would be surprised by various smart devices like,for example,smart teapot.Furthermore,people find these tools really convenient and useful.However,in order to ensure technical implementation that would be able to provide decent quality,next generation of wireless communications need to provide significantly high rate(apparently of Gbps),exceedingly low latency,extreme enlargement in Base Station(BS)capacity.Moreover,5G would pursue considerable enhancement in perceived Quality of Service(QoS)comparing existing 4G LTE networks.Above mentioned dissemination of smart devices,as well as injection of diverse multimedia applications,together with almost exponential rise in wireless data(mainly multimedia)requirement and usage is already establishing a considerable load on nowadays utilizing cellular networks.Thus,5G wireless systems exploiting better data rates,capacity,latency should become the cure for the most existing problems of cellular networks.This survey consists of several parts,thus there could be distinguished three main research directions.These are: comprehensive survey over 5G Wireless Networks,handover performance in 5G HetNets and Authentication handover mechanism that would accelerate authentication in 5G HetNets by enabling SCI transfer using SDN.First and foremost,a comprehensive survey of wireless development toward 5G networks.Initially,novice architectural changes,which are interconnected with the Radio Access Network(RAN)design,such as Air Interfaces,Smart Antennas,Cloud and Heterogenous RAN.Afterward,considerably deep survey of beneath mm-wave physical layer technologies,along with directional antenna,beamforming schemes,massive MIMO technologies.Further,details of MAC layer acknowledgements are provided,that are essential to support new physical layer.In order to realize the demand for user experience,features of emerging QoS,QOE,SON are also discussed.To mitigate requirements of operation costs and energy consumption,corresponding topics are displayed.Above all,paper demonstrates major existing research obstacles and points.Secondly,handover performance is considered.Heterogenous deployment of macro cells and small cells seems to be a pivotal network topology in future generation cellular networks.This layout could effective and competently improve network capacity and coverage.Millimeter wave(mmWave)frequencies would be used in 5G Heterogenous Networks(HetNets).A typical scenario of such HetNets is that mmWave base stations(BSs)are utilized in macro cells to provide high-capacity coverage in hotspots.Directional communication is a vital way for mmWave small cells to enhance its coverage area and to decrease interference.Handover(HO)as a substantial point for mobility management,plays an important role in HetNets.In conducting research,the impact of the distance among the overlaid macro BSs and the mmWave small BSs with directional antenna setups on the HO performance is shown.Expression of the probabilities of HO,no HO and HO failure are obtained.Furthermore,simulation results are received to validate the analytical results.Finally,another objective of a study is to simplify authentication handover by global management of 5G HetNets through sharing of user-dependent security context information among related access points.It would be demonstrated that SDN-enabled security solutions are highly efficient through its centralized control capability,which is essential for strict 5G communications.A design goal for this part of paper is an authentication handover mechanism that would accelerate authentication in 5G Network by enabling SCI transfer using SDN. |
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