Key technologies for 5G, the next generation of mobile networks and services (2016)

The advance of mobile networks and services has brought us great convenience in our daily life. However, the pursuit of human beings is endless. Following the great success of 2G and 3G mobile networks and the fast growth of 4G, the 5th generation of mobile networks and wireless systems (in short 5G) was proposed to offer “infinite” networking capabilities and unrivalled user experiences for mobile users at any time and in any places and situations. A number of governments, telecommunication companies (eg, Samsung, Huawei, Ericsson, Nokia, and Telefonica Europe), and scientific researchers have initiated big research and development efforts on 5G in recent years. When compared to 4G, 5G brings much more than increased maximum throughput. While 3G and 4G were driven by services and by network operators, 5G is more user centric and pursues toward “infinite” networking capability experienced by users. It aims to involve and benefit from many current technical advances including software-defined networking (SDN), network functions virtualization (NFV), interference and mobility management, Internet of things (IoT), data mining, pervasive and social computing, mobile ad hoc networks (MANET), cognitive radio, world wide wireless web (WWWW), cloud computing, and IPv6. Obviously, the development and deployment of 5G will reversely contribute to progress of many existing technologies, such as social networking and cloud computing, as well as IoT. What are the key technologies to make 5G fly? What are the perspectives of 5G architecture and security? How to effectively apply and benefit from the above technologies and make them interoperate in optimal way and support with each other in 5G? How can 5G stimulate our innovation? Obviously, integrating existing advanced technologies and innovating new techniques for 5G bring extreme challenges on 5G networks, security, implementation and applications, and services. A number of crucial issues such as 5G security and trust, transmission collaboration, intelligent and usable 5G service provision, privacy preservation and identity management, seamless and secure integration of all available networking resources, heterogeneous network fusion, high-speed network connectivity, smart 5G terminals, 5G quality of service (QoS) management, and energy efficiency have not been thoroughly explored and studied. Without any doubt, 5G introduces tremendous challenges in both research and development. This study has just been initiated in both industry and academia, but with great fervor. This special issue aims at discussing the perspective of 5G, explores key 5G technologies, innovates new techniques and solutions for 5G, and investigates technology enablers and business aspects for the next generation mobile networks and services. We accepted 8 articles from many submissions after rigorous peer review. Each article is briefly introduced below. In the article “Cooperative Multi-cellular Large MIMO over Asynchronous Channel Training,” the authors investigated the deployment of different training sequence sets for channel estimation in a multicell massive MIMO environment with cooperation between base stations. An analytical expression for evaluating the performance of training sequence-based channel estimation was proposed with a number of valuable findings. The 5G era will enable many interesting applications about IoT-based services, where security is significantly important. In the article “Security Protocols in Body Sensor Networks Using Visible Light Communications,” Huang et al proposed 2 key establishment protocols for body sensor networks by using visible light communications (VLCs) to set up a secure channel among sensors without any needs on preshared secrets. In the article “Data Transfer Minimization for Financial Derivative Pricing Using Monte Carlo Simulation with GPU in 5G,” Qiu et al proposed a novel paradigm for preventing future mobile technology implementations from the restrictions of hardware by using graphics processing units (GPUs). The article “Keep all Mobile Users' Whereabouts Secure: An RFID Protocol Anti-Tracking in 5G” proposes a hash-based mutual authentication protocol for smartphones in 5G to eliminate location-tracking threats and distributed denial of service (DDoS) attacks on back-end servers. In 5G, femtocells will play a major role for providing cost-efficient improvement in data rates and coverage. In the article “Transmission Optimizing on Dense Femtocell deployments in 5G,” the authors presented a mechanism where multiple femtocells coordinate their transmission to serve multiple nonsubscribed users through hybrid access to improve the throughput of the nonsubscribed users connected to femtocell and the most impacted subscribed users at weak macrocell signal areas. In “Smartphone-based Activity Recognition Independent of Device Orientation and Placement,” Guo et al proposed a smartphone-based activity recognition method that is independent of device orientation and placement and solves a smartphone-based activity recognition problem with sound precision. Yu et al proposed a novel routing algorithm in delay tolerant networks on the basis of hybrid of message delivery probability and message redundancy to reduce the communication overhead while keeping a high message delivery ratio. Refer to the article “Probabilistic Routing Algorithm based on Contact Duration and Message Redundancy in Delay Tolerant Network” for details. The article “Belief Propagation Based Compressed Video Sensing for Mobile Internet” presents a compressed video-sensing framework for mobile Internet with a belief propagation algorithm and a proposed video signal model. It can efficiently use the temporal correlation in video and obtain improved reconstruction quality and robust performance in wireless communication systems toward 5G. We would like to thank all reviewers for their professional work. We appreciate the support of Professor Mohammad S. Obaidat, the Editor-in-Chief of IJCS during the editing of this special issue. The research on 5G technologies has just initiated. We hope this special issue can motivate additional efforts for achieving practical results to make 5G come true. This work is sponsored by the National Key Foundational Research and Development on Network and Space Security, China (grant 2016YFB0800704), the NSFC (grants 61672410 and U1536202), the PhD grant of the Ministry of Education, China (grant JY0300130104), the Project Supported by Natural Science Basic Research Plan in Shaanxi Province of China (Program no. 2016ZDJC-06), the 111 project (grants B08038 and B16037), and the Aalto University.